diff --git a/SabreTools.Core/ConcurrentList.cs b/SabreTools.Core/ConcurrentList.cs
index b1c2b484..938486f1 100644
--- a/SabreTools.Core/ConcurrentList.cs
+++ b/SabreTools.Core/ConcurrentList.cs
@@ -18,7 +18,7 @@ namespace SabreTools.Core
             set { lock (_lock) _list[index] = value; }
         }
 
-        object IList.this[int index]
+        object? IList.this[int index]
         {
             get { lock (_lock) return ((IList)_list)[index]; }
             set { lock (_lock) ((IList)_list)[index] = value; }
@@ -43,7 +43,7 @@ namespace SabreTools.Core
                 _list.Add(item);
         }
 
-        public int Add(object value)
+        public int Add(object? value)
         {
             lock (_lock)
                 return ((IList)_list).Add(value);
@@ -67,7 +67,7 @@ namespace SabreTools.Core
                 return _list.Contains(item);
         }
 
-        public bool Contains(object value)
+        public bool Contains(object? value)
         {
             lock (_lock)
                 return ((IList)_list).Contains(value);
@@ -109,7 +109,7 @@ namespace SabreTools.Core
                 return _list.IndexOf(item);
         }
 
-        public int IndexOf(object value)
+        public int IndexOf(object? value)
         {
             lock (_lock)
                 return ((IList)_list).IndexOf(value);
@@ -121,7 +121,7 @@ namespace SabreTools.Core
                 _list.Insert(index, item);
         }
 
-        public void Insert(int index, object value)
+        public void Insert(int index, object? value)
         {
             lock (_lock)
                 ((IList)_list).Insert(index, value);
@@ -133,7 +133,7 @@ namespace SabreTools.Core
                 return _list.Remove(item);
         }
 
-        public void Remove(object value)
+        public void Remove(object? value)
         {
             lock (_lock)
                 ((IList)_list).Remove(value);
diff --git a/SabreTools.Core/NaturalSort/NaturalComparer.cs b/SabreTools.Core/NaturalSort/NaturalComparer.cs
index c08cbd93..ae3a55b9 100644
--- a/SabreTools.Core/NaturalSort/NaturalComparer.cs
+++ b/SabreTools.Core/NaturalSort/NaturalComparer.cs
@@ -14,82 +14,91 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text.RegularExpressions;
 
+// TODO: Split into separate library
 namespace NaturalSort
 {
-	public class NaturalComparer : Comparer<string>, IDisposable
-	{
-		private Dictionary<string, string[]> table;
+    public class NaturalComparer : Comparer<string>, IDisposable
+    {
+        private readonly Dictionary<string, string[]> table;
 
-		public NaturalComparer()
-		{
-			table = new Dictionary<string, string[]>();
-		}
+        public NaturalComparer()
+        {
+            table = new Dictionary<string, string[]>();
+        }
 
         public void Dispose()
-		{
-			table.Clear();
-			table = null;
-		}
+        {
+            table.Clear();
+        }
 
-		public override int Compare(string x, string y)
-		{
-			if (x.ToLowerInvariant() == y.ToLowerInvariant())
-			{
-				return x.CompareTo(y);
-			}
-			if (!table.TryGetValue(x, out string[] x1))
-			{
-				//x1 = Regex.Split(x.Replace(" ", string.Empty), "([0-9]+)");
-				x1 = Regex.Split(x.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
-				table.Add(x, x1);
-			}
-			if (!table.TryGetValue(y, out string[] y1))
-			{
-				//y1 = Regex.Split(y.Replace(" ", string.Empty), "([0-9]+)");
-				y1 = Regex.Split(y.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
-				table.Add(y, y1);
-			}
+        public override int Compare(string? x, string? y)
+        {
+            if (x == null || y == null)
+            {
+                if (x == null && y != null)
+                    return -1;
+                else if (x != null && y == null)
+                    return 1;
+                else
+                    return 0;
+            }
+            if (x.ToLowerInvariant() == y.ToLowerInvariant())
+            {
+                return x.CompareTo(y);
+            }
+            if (!table.TryGetValue(x, out string[]? x1))
+            {
+                //x1 = Regex.Split(x.Replace(" ", string.Empty), "([0-9]+)");
+                x1 = Regex.Split(x.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
+                table.Add(x, x1);
+            }
+            if (!table.TryGetValue(y, out string[]? y1))
+            {
+                //y1 = Regex.Split(y.Replace(" ", string.Empty), "([0-9]+)");
+                y1 = Regex.Split(y.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
+                table.Add(y, y1);
+            }
 
-			for (int i = 0; i < x1.Length && i < y1.Length; i++)
-			{
-				if (x1[i] != y1[i])
-				{
-					return PartCompare(x1[i], y1[i]);
-				}
-			}
-			if (y1.Length > x1.Length)
-			{
-				return 1;
-			}
-			else if (x1.Length > y1.Length)
-			{
-				return -1;
-			}
-			else
-			{
-				return x.CompareTo(y);
-			}
-		}
+            for (int i = 0; i < x1.Length && i < y1.Length; i++)
+            {
+                if (x1[i] != y1[i])
+                {
+                    return PartCompare(x1[i], y1[i]);
+                }
+            }
+            if (y1.Length > x1.Length)
+            {
+                return 1;
+            }
+            else if (x1.Length > y1.Length)
+            {
+                return -1;
+            }
+            else
+            {
+                return x.CompareTo(y);
+            }
+        }
 
-		private static int PartCompare(string left, string right)
-		{
-			if (!long.TryParse(left, out long x))
-			{
-				return NaturalComparerUtil.CompareNumeric(left, right);
-			}
+        private static int PartCompare(string left, string right)
+        {
+            if (!long.TryParse(left, out long x))
+            {
+                return NaturalComparerUtil.CompareNumeric(left, right);
+            }
 
-			if (!long.TryParse(right, out long y))
-			{
-				return NaturalComparerUtil.CompareNumeric(left, right);
-			}
+            if (!long.TryParse(right, out long y))
+            {
+                return NaturalComparerUtil.CompareNumeric(left, right);
+            }
 
-			// If we have an equal part, then make sure that "longer" ones are taken into account
-			if (x.CompareTo(y) == 0)
-			{
-				return left.Length - right.Length;
-			}
+            // If we have an equal part, then make sure that "longer" ones are taken into account
+            if (x.CompareTo(y) == 0)
+            {
+                return left.Length - right.Length;
+            }
 
-			return x.CompareTo(y);
-		}
-	}
+            return x.CompareTo(y);
+        }
+    }
 }
diff --git a/SabreTools.Core/NaturalSort/NaturalComparerUtil.cs b/SabreTools.Core/NaturalSort/NaturalComparerUtil.cs
index d13318c3..86158295 100644
--- a/SabreTools.Core/NaturalSort/NaturalComparerUtil.cs
+++ b/SabreTools.Core/NaturalSort/NaturalComparerUtil.cs
@@ -1,78 +1,79 @@
 using System.IO;
 
+// TODO: Split into separate library
 namespace NaturalSort
 {
     public static class NaturalComparerUtil
     {
-		public static int CompareNumeric(string s1, string s2)
-		{
-			// Save the orginal strings, for later comparison
-			string s1orig = s1;
-			string s2orig = s2;
+        public static int CompareNumeric(string s1, string s2)
+        {
+            // Save the orginal strings, for later comparison
+            string s1orig = s1;
+            string s2orig = s2;
 
-			// We want to normalize the strings, so we set both to lower case
-			s1 = s1.ToLowerInvariant();
-			s2 = s2.ToLowerInvariant();
+            // We want to normalize the strings, so we set both to lower case
+            s1 = s1.ToLowerInvariant();
+            s2 = s2.ToLowerInvariant();
 
-			// If the strings are the same exactly, return
-			if (s1 == s2)
-				return s1orig.CompareTo(s2orig);
+            // If the strings are the same exactly, return
+            if (s1 == s2)
+                return s1orig.CompareTo(s2orig);
 
-			// If one is null, then say that's less than
-			if (s1 == null)
-				return -1;
-			if (s2 == null)
-				return 1;
+            // If one is null, then say that's less than
+            if (s1 == null)
+                return -1;
+            if (s2 == null)
+                return 1;
 
-			// Now split into path parts after converting AltDirSeparator to DirSeparator
-			s1 = s1.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
-			s2 = s2.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
-			string[] s1parts = s1.Split(Path.DirectorySeparatorChar);
-			string[] s2parts = s2.Split(Path.DirectorySeparatorChar);
+            // Now split into path parts after converting AltDirSeparator to DirSeparator
+            s1 = s1.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
+            s2 = s2.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
+            string[] s1parts = s1.Split(Path.DirectorySeparatorChar);
+            string[] s2parts = s2.Split(Path.DirectorySeparatorChar);
 
-			// Then compare each part in turn
-			for (int j = 0; j < s1parts.Length && j < s2parts.Length; j++)
-			{
-				int compared = CompareNumericPart(s1parts[j], s2parts[j]);
-				if (compared != 0)
-					return compared;
-			}
+            // Then compare each part in turn
+            for (int j = 0; j < s1parts.Length && j < s2parts.Length; j++)
+            {
+                int compared = CompareNumericPart(s1parts[j], s2parts[j]);
+                if (compared != 0)
+                    return compared;
+            }
 
-			// If we got out here, then it looped through at least one of the strings
-			if (s1parts.Length > s2parts.Length)
-				return 1;
-			if (s1parts.Length < s2parts.Length)
-				return -1;
+            // If we got out here, then it looped through at least one of the strings
+            if (s1parts.Length > s2parts.Length)
+                return 1;
+            if (s1parts.Length < s2parts.Length)
+                return -1;
 
-			return s1orig.CompareTo(s2orig);
-		}
+            return s1orig.CompareTo(s2orig);
+        }
 
-		private static int CompareNumericPart(string s1, string s2)
-		{
-			// Otherwise, loop through until we have an answer
-			for (int i = 0; i < s1.Length && i < s2.Length; i++)
-			{
-				int s1c = s1[i];
-				int s2c = s2[i];
+        private static int CompareNumericPart(string s1, string s2)
+        {
+            // Otherwise, loop through until we have an answer
+            for (int i = 0; i < s1.Length && i < s2.Length; i++)
+            {
+                int s1c = s1[i];
+                int s2c = s2[i];
 
-				// If the characters are the same, continue
-				if (s1c == s2c)
-					continue;
+                // If the characters are the same, continue
+                if (s1c == s2c)
+                    continue;
 
-				// If they're different, check which one was larger
-				if (s1c > s2c)
-					return 1;
-				if (s1c < s2c)
-					return -1;
-			}
+                // If they're different, check which one was larger
+                if (s1c > s2c)
+                    return 1;
+                if (s1c < s2c)
+                    return -1;
+            }
 
-			// If we got out here, then it looped through at least one of the strings
-			if (s1.Length > s2.Length)
-				return 1;
-			if (s1.Length < s2.Length)
-				return -1;
+            // If we got out here, then it looped through at least one of the strings
+            if (s1.Length > s2.Length)
+                return 1;
+            if (s1.Length < s2.Length)
+                return -1;
 
-			return 0;
-		}
-	}
+            return 0;
+        }
+    }
 }
diff --git a/SabreTools.Core/NaturalSort/NaturalReversedComparer.cs b/SabreTools.Core/NaturalSort/NaturalReversedComparer.cs
index da591f1a..d0a44975 100644
--- a/SabreTools.Core/NaturalSort/NaturalReversedComparer.cs
+++ b/SabreTools.Core/NaturalSort/NaturalReversedComparer.cs
@@ -14,82 +14,91 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text.RegularExpressions;
 
+// TODO: Split into separate library
 namespace NaturalSort
 {
-	public class NaturalReversedComparer : Comparer<string>, IDisposable
-	{
-		private Dictionary<string, string[]> table;
+    public class NaturalReversedComparer : Comparer<string>, IDisposable
+    {
+        private readonly Dictionary<string, string[]> table;
 
-		public NaturalReversedComparer()
-		{
-			table = new Dictionary<string, string[]>();
-		}
+        public NaturalReversedComparer()
+        {
+            table = new Dictionary<string, string[]>();
+        }
 
-		public void Dispose()
-		{
-			table.Clear();
-			table = null;
-		}
+        public void Dispose()
+        {
+            table.Clear();
+        }
 
-		public override int Compare(string x, string y)
-		{
-			if (y.ToLowerInvariant() == x.ToLowerInvariant())
-			{
-				return y.CompareTo(x);
-			}
-			if (!table.TryGetValue(x, out string[] x1))
-			{
-				//x1 = Regex.Split(x.Replace(" ", string.Empty), "([0-9]+)");
-				x1 = Regex.Split(x.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
-				table.Add(x, x1);
-			}
-			if (!table.TryGetValue(y, out string[] y1))
-			{
-				//y1 = Regex.Split(y.Replace(" ", string.Empty), "([0-9]+)");
-				y1 = Regex.Split(y.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
-				table.Add(y, y1);
-			}
+        public override int Compare(string? x, string? y)
+        {
+            if (x == null || y == null)
+            {
+                if (x == null && y != null)
+                    return -1;
+                else if (x != null && y == null)
+                    return 1;
+                else
+                    return 0;
+            }
+            if (y.ToLowerInvariant() == x.ToLowerInvariant())
+            {
+                return y.CompareTo(x);
+            }
+            if (!table.TryGetValue(x, out string[]? x1))
+            {
+                //x1 = Regex.Split(x.Replace(" ", string.Empty), "([0-9]+)");
+                x1 = Regex.Split(x.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
+                table.Add(x, x1);
+            }
+            if (!table.TryGetValue(y, out string[]? y1))
+            {
+                //y1 = Regex.Split(y.Replace(" ", string.Empty), "([0-9]+)");
+                y1 = Regex.Split(y.ToLowerInvariant(), "([0-9]+)").Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();
+                table.Add(y, y1);
+            }
 
-			for (int i = 0; i < x1.Length && i < y1.Length; i++)
-			{
-				if (x1[i] != y1[i])
-				{
-					return PartCompare(x1[i], y1[i]);
-				}
-			}
-			if (y1.Length > x1.Length)
-			{
-				return 1;
-			}
-			else if (x1.Length > y1.Length)
-			{
-				return -1;
-			}
-			else
-			{
-				return y.CompareTo(x);
-			}
-		}
+            for (int i = 0; i < x1.Length && i < y1.Length; i++)
+            {
+                if (x1[i] != y1[i])
+                {
+                    return PartCompare(x1[i], y1[i]);
+                }
+            }
+            if (y1.Length > x1.Length)
+            {
+                return 1;
+            }
+            else if (x1.Length > y1.Length)
+            {
+                return -1;
+            }
+            else
+            {
+                return y.CompareTo(x);
+            }
+        }
 
-		private static int PartCompare(string left, string right)
-		{
-			if (!long.TryParse(left, out long x))
-			{
-				return NaturalComparerUtil.CompareNumeric(right, left);
-			}
+        private static int PartCompare(string left, string right)
+        {
+            if (!long.TryParse(left, out long x))
+            {
+                return NaturalComparerUtil.CompareNumeric(right, left);
+            }
 
-			if (!long.TryParse(right, out long y))
-			{
-				return NaturalComparerUtil.CompareNumeric(right, left);
-			}
+            if (!long.TryParse(right, out long y))
+            {
+                return NaturalComparerUtil.CompareNumeric(right, left);
+            }
 
-			// If we have an equal part, then make sure that "longer" ones are taken into account
-			if (y.CompareTo(x) == 0)
-			{
-				return right.Length - left.Length;
-			}
+            // If we have an equal part, then make sure that "longer" ones are taken into account
+            if (y.CompareTo(x) == 0)
+            {
+                return right.Length - left.Length;
+            }
 
-			return y.CompareTo(x);
-		}
-	}
+            return y.CompareTo(x);
+        }
+    }
 }
diff --git a/SabreTools.Core/Prepare.cs b/SabreTools.Core/Prepare.cs
index 1070fb87..551fb86c 100644
--- a/SabreTools.Core/Prepare.cs
+++ b/SabreTools.Core/Prepare.cs
@@ -13,7 +13,7 @@ namespace SabreTools.Core
         /// The current toolset version to be used by all child applications
         /// </summary>
         public readonly static string Version = $"v1.1.2";
- 
+
         /// <summary>
         /// Readies the console and outputs the header
         /// </summary>
@@ -30,9 +30,6 @@ namespace SabreTools.Core
             if (!Console.IsOutputRedirected)
             {
                 // Set the console to ready state
-                if (Environment.OSVersion.Platform == PlatformID.Win32NT)
-                    Console.SetBufferSize(Console.BufferWidth, 999);
-
                 ConsoleColor formertext = Console.ForegroundColor;
                 ConsoleColor formerback = Console.BackgroundColor;
                 Console.ForegroundColor = ConsoleColor.Yellow;
@@ -48,7 +45,7 @@ namespace SabreTools.Core
 
                 // Return the console to the original text and background colors
                 Console.ForegroundColor = formertext;
-                    Console.BackgroundColor = formerback;
+                Console.BackgroundColor = formerback;
             }
         }
     }
diff --git a/SabreTools.Core/SabreTools.Core.csproj b/SabreTools.Core/SabreTools.Core.csproj
index 0f080476..9e23202e 100644
--- a/SabreTools.Core/SabreTools.Core.csproj
+++ b/SabreTools.Core/SabreTools.Core.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/SabreTools.Core/Tools/Aaru/SpamSumContext.cs b/SabreTools.Core/Tools/Aaru/SpamSumContext.cs
index cd4eb26a..94e4ea28 100644
--- a/SabreTools.Core/Tools/Aaru/SpamSumContext.cs
+++ b/SabreTools.Core/Tools/Aaru/SpamSumContext.cs
@@ -454,7 +454,7 @@ namespace Aaru.Checksums
         /// <param name="len">Length of the data buffer to hash.</param>
         /// <param name="hash">null</param>
         /// <returns>Base64 representation of SpamSum $blocksize:$hash:$hash</returns>
-        public static string Data(byte[] data, uint len, out byte[] hash)
+        public static string Data(byte[] data, uint len, out byte[]? hash)
         {
             var fuzzyContext = new SpamSumContext();
 
@@ -469,7 +469,7 @@ namespace Aaru.Checksums
         /// <param name="data">Data buffer.</param>
         /// <param name="hash">null</param>
         /// <returns>Base64 representation of SpamSum $blocksize:$hash:$hash</returns>
-        public static string Data(byte[] data, out byte[] hash) => Data(data, (uint)data.Length, out hash);
+        public static string Data(byte[] data, out byte[]? hash) => Data(data, (uint)data.Length, out hash);
 
         // Converts an ASCII null-terminated string to .NET string
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
diff --git a/SabreTools.Core/Tools/AttributeHelper.cs b/SabreTools.Core/Tools/AttributeHelper.cs
index 8c31f5eb..1014904c 100644
--- a/SabreTools.Core/Tools/AttributeHelper.cs
+++ b/SabreTools.Core/Tools/AttributeHelper.cs
@@ -10,7 +10,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="value">Value to use</param>
         /// <returns>MappingAttribute attached to the value</returns>
-        public static MappingAttribute GetAttribute(T value)
+        public static MappingAttribute? GetAttribute(T? value)
         {
             // Null value in, null value out
             if (value == null)
@@ -22,7 +22,7 @@ namespace SabreTools.Core.Tools
                 enumType = Nullable.GetUnderlyingType(enumType);
 
             // If the value returns a null on ToString, just return null
-            string valueStr = value.ToString();
+            string? valueStr = value.ToString();
             if (string.IsNullOrWhiteSpace(valueStr))
                 return null;
             
@@ -42,7 +42,7 @@ namespace SabreTools.Core.Tools
                 return null;
             
             // Return the first attribute, if possible
-            return (MappingAttribute)attributes.FirstOrDefault();
+            return (MappingAttribute?)attributes.FirstOrDefault();
         }
     }
 }
\ No newline at end of file
diff --git a/SabreTools.Core/Tools/Converters.cs b/SabreTools.Core/Tools/Converters.cs
index 9843f0b3..854f0182 100644
--- a/SabreTools.Core/Tools/Converters.cs
+++ b/SabreTools.Core/Tools/Converters.cs
@@ -43,7 +43,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="chipType">String to get value from</param>
         /// <returns>ChipType value corresponding to the string</returns>
-        public static ChipType AsChipType(this string chipType)
+        public static ChipType AsChipType(this string? chipType)
             => AsEnumValue<ChipType>(chipType);
 
         /// <summary>
@@ -51,7 +51,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="controlType">String to get value from</param>
         /// <returns>ControlType value corresponding to the string</returns>
-        public static ControlType AsControlType(this string controlType)
+        public static ControlType AsControlType(this string? controlType)
             => AsEnumValue<ControlType>(controlType);
 
         /// <summary>
@@ -59,7 +59,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="DatHeaderField">String to get value from</param>
         /// <returns>DatHeaderField value corresponding to the string</returns>
-        public static DatHeaderField AsDatHeaderField(this string input)
+        public static DatHeaderField AsDatHeaderField(this string? input)
         {
             // If the input is empty, we return null
             if (string.IsNullOrEmpty(input))
@@ -89,7 +89,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="input">String to get value from</param>
         /// <returns>DatItemField value corresponding to the string</returns>
-        public static DatItemField AsDatItemField(this string input)
+        public static DatItemField AsDatItemField(this string? input)
         {
             // If the input is empty, we return null
             if (string.IsNullOrEmpty(input))
@@ -119,7 +119,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="deviceType">String to get value from</param>
         /// <returns>DeviceType value corresponding to the string</returns>
-        public static DeviceType AsDeviceType(this string deviceType)
+        public static DeviceType AsDeviceType(this string? deviceType)
             => AsEnumValue<DeviceType>(deviceType);
 
         /// <summary>
@@ -127,7 +127,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="displayType">String to get value from</param>
         /// <returns>DisplayType value corresponding to the string</returns>
-        public static DisplayType AsDisplayType(this string displayType)
+        public static DisplayType AsDisplayType(this string? displayType)
             => AsEnumValue<DisplayType>(displayType);
 
         /// <summary>
@@ -135,7 +135,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="endianness">String to get value from</param>
         /// <returns>Endianness value corresponding to the string</returns>
-        public static Endianness AsEndianness(this string endianness)
+        public static Endianness AsEndianness(this string? endianness)
             => AsEnumValue<Endianness>(endianness);
 
         /// <summary>
@@ -143,7 +143,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="featureStatus">String to get value from</param>
         /// <returns>FeatureStatus value corresponding to the string</returns>
-        public static FeatureStatus AsFeatureStatus(this string featureStatus)
+        public static FeatureStatus AsFeatureStatus(this string? featureStatus)
             => AsEnumValue<FeatureStatus>(featureStatus);
 
         /// <summary>
@@ -151,7 +151,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="emulationStatus">String to get value from</param>
         /// <returns>FeatureType value corresponding to the string</returns>
-        public static FeatureType AsFeatureType(this string featureType)
+        public static FeatureType AsFeatureType(this string? featureType)
             => AsEnumValue<FeatureType>(featureType);
 
         /// <summary>
@@ -159,7 +159,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="status">String to get value from</param>
         /// <returns>ItemStatus value corresponding to the string</returns>
-        public static ItemStatus AsItemStatus(this string status)
+        public static ItemStatus AsItemStatus(this string? status)
             => AsEnumValue<ItemStatus>(status);
 
         /// <summary>
@@ -167,7 +167,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="itemType">String to get value from</param>
         /// <returns>ItemType? value corresponding to the string</returns>
-        public static ItemType AsItemType(this string itemType)
+        public static ItemType AsItemType(this string? itemType)
             => AsEnumValue<ItemType>(itemType);
 
         /// <summary>
@@ -175,7 +175,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="loadFlag">String to get value from</param>
         /// <returns>LoadFlag value corresponding to the string</returns>
-        public static LoadFlag AsLoadFlag(this string loadFlag)
+        public static LoadFlag AsLoadFlag(this string? loadFlag)
             => AsEnumValue<LoadFlag>(loadFlag);
 
         /// <summary>
@@ -183,7 +183,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="logLevel">String to get value from</param>
         /// <returns>LogLevel value corresponding to the string</returns>
-        public static LogLevel AsLogLevel(this string logLevel)
+        public static LogLevel AsLogLevel(this string? logLevel)
             => AsEnumValue<LogLevel>(logLevel);
 
         /// <summary>
@@ -191,7 +191,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="input">String to get value from</param>
         /// <returns>MachineField value corresponding to the string</returns>
-        public static MachineField AsMachineField(this string input)
+        public static MachineField AsMachineField(this string? input)
         {
             // If the input is empty, we return null
             if (string.IsNullOrEmpty(input))
@@ -221,7 +221,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="gametype">String to get value from</param>
         /// <returns>MachineType value corresponding to the string</returns>
-        public static MachineType AsMachineType(this string gametype)
+        public static MachineType AsMachineType(this string? gametype)
             => AsEnumValue<MachineType>(gametype);
 
         /// <summary>
@@ -229,7 +229,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="merging">String to get value from</param>
         /// <returns>MergingFlag value corresponding to the string</returns>
-        public static MergingFlag AsMergingFlag(this string merging)
+        public static MergingFlag AsMergingFlag(this string? merging)
             => AsEnumValue<MergingFlag>(merging);
 
         /// <summary>
@@ -237,7 +237,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="nodump">String to get value from</param>
         /// <returns>NodumpFlag value corresponding to the string</returns>
-        public static NodumpFlag AsNodumpFlag(this string nodump)
+        public static NodumpFlag AsNodumpFlag(this string? nodump)
             => AsEnumValue<NodumpFlag>(nodump);
 
         /// <summary>
@@ -245,7 +245,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="subType">String to get value from</param>
         /// <returns>OpenMSXSubType value corresponding to the string</returns>
-        public static OpenMSXSubType AsOpenMSXSubType(this string subType)
+        public static OpenMSXSubType AsOpenMSXSubType(this string? subType)
             => AsEnumValue<OpenMSXSubType>(subType);
 
         /// <summary>
@@ -253,7 +253,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="packing">String to get value from</param>
         /// <returns>PackingFlag value corresponding to the string</returns>
-        public static PackingFlag AsPackingFlag(this string packing)
+        public static PackingFlag AsPackingFlag(this string? packing)
             => AsEnumValue<PackingFlag>(packing);
 
         /// <summary>
@@ -261,7 +261,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="relation">String to get value from</param>
         /// <returns>Relation value corresponding to the string</returns>
-        public static Relation AsRelation(this string relation)
+        public static Relation AsRelation(this string? relation)
             => AsEnumValue<Relation>(relation);
 
         /// <summary>
@@ -269,7 +269,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="runnable">String to get value from</param>
         /// <returns>Runnable value corresponding to the string</returns>
-        public static Runnable AsRunnable(this string runnable)
+        public static Runnable AsRunnable(this string? runnable)
             => AsEnumValue<Runnable>(runnable);
 
         /// <summary>
@@ -277,7 +277,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="status">String to get value from</param>
         /// <returns>SoftwareListStatus value corresponding to the string</returns>
-        public static SoftwareListStatus AsSoftwareListStatus(this string status)
+        public static SoftwareListStatus AsSoftwareListStatus(this string? status)
             => AsEnumValue<SoftwareListStatus>(status);
 
         /// <summary>
@@ -285,7 +285,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="supported">String to get value from</param>
         /// <returns>Supported value corresponding to the string</returns>
-        public static Supported AsSupported(this string supported)
+        public static Supported AsSupported(this string? supported)
             => AsEnumValue<Supported>(supported);
 
         /// <summary>
@@ -293,7 +293,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="supported">String to get value from</param>
         /// <returns>SupportStatus value corresponding to the string</returns>
-        public static SupportStatus AsSupportStatus(this string supportStatus)
+        public static SupportStatus AsSupportStatus(this string? supportStatus)
             => AsEnumValue<SupportStatus>(supportStatus);
 
         /// <summary>
@@ -301,7 +301,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="yesno">String to get value from</param>
         /// <returns>bool? corresponding to the string</returns>
-        public static bool? AsYesNo(this string yesno)
+        public static bool? AsYesNo(this string? yesno)
         {
             return yesno?.ToLowerInvariant() switch
             {
@@ -317,7 +317,7 @@ namespace SabreTools.Core.Tools
         /// <param name="value">String value to parse/param>
         /// <typeparam name="T">Enum type that is expected</typeparam>
         /// <returns>Enum value representing the input, default on error</returns>
-        internal static T AsEnumValue<T>(string value)
+        internal static T? AsEnumValue<T>(string? value)
         {
             // Get the mapping dictionary
             var mappings = GenerateToEnum<T>();
@@ -352,7 +352,7 @@ namespace SabreTools.Core.Tools
                 foreach (T value in values)
                 {
                     // Try to get the mapping attribute
-                    MappingAttribute attr = AttributeHelper<T>.GetAttribute(value);
+                    MappingAttribute? attr = AttributeHelper<T>.GetAttribute(value);
                     if (attr?.Mappings == null || !attr.Mappings.Any())
                         continue;
 
@@ -383,7 +383,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="chipType">ChipType to get value from</param>
         /// <returns>String value corresponding to the ChipType</returns>
-        public static string FromChipType(this ChipType chipType)
+        public static string? FromChipType(this ChipType chipType)
             => AsStringValue(chipType);
 
         /// <summary>
@@ -391,7 +391,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="controlType">ControlType to get value from</param>
         /// <returns>String value corresponding to the ControlType</returns>
-        public static string FromControlType(this ControlType controlType)
+        public static string? FromControlType(this ControlType controlType)
             => AsStringValue(controlType);
 
         /// <summary>
@@ -399,7 +399,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="deviceType">vDeviceType to get value from</param>
         /// <returns>String value corresponding to the DeviceType</returns>
-        public static string FromDeviceType(this DeviceType deviceType)
+        public static string? FromDeviceType(this DeviceType deviceType)
             => AsStringValue(deviceType);
 
         /// <summary>
@@ -407,7 +407,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="displayType">DisplayType to get value from</param>
         /// <returns>String value corresponding to the DisplayType</returns>
-        public static string FromDisplayType(this DisplayType displayType)
+        public static string? FromDisplayType(this DisplayType displayType)
             => AsStringValue(displayType);
 
         /// <summary>
@@ -415,7 +415,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="endianness">Endianness to get value from</param>
         /// <returns>String value corresponding to the Endianness</returns>
-        public static string FromEndianness(this Endianness endianness)
+        public static string? FromEndianness(this Endianness endianness)
             => AsStringValue(endianness);
 
         /// <summary>
@@ -423,7 +423,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="featureStatus">FeatureStatus to get value from</param>
         /// <returns>String value corresponding to the FeatureStatus</returns>
-        public static string FromFeatureStatus(this FeatureStatus featureStatus)
+        public static string? FromFeatureStatus(this FeatureStatus featureStatus)
             => AsStringValue(featureStatus);
 
         /// <summary>
@@ -431,7 +431,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="featureType">FeatureType to get value from</param>
         /// <returns>String value corresponding to the FeatureType</returns>
-        public static string FromFeatureType(this FeatureType featureType)
+        public static string? FromFeatureType(this FeatureType featureType)
             => AsStringValue(featureType);
 
         /// <summary>
@@ -440,7 +440,7 @@ namespace SabreTools.Core.Tools
         /// <param name="status">ItemStatus to get value from</param>
         /// <param name="yesno">True to use Yes/No format instead</param>
         /// <returns>String value corresponding to the ItemStatus</returns>
-        public static string FromItemStatus(this ItemStatus status, bool yesno)
+        public static string? FromItemStatus(this ItemStatus status, bool yesno)
             => AsStringValue(status, yesno);
 
         /// <summary>
@@ -448,7 +448,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="itemType">ItemType? to get value from</param>
         /// <returns>String value corresponding to the ItemType?</returns>
-        public static string FromItemType(this ItemType itemType)
+        public static string? FromItemType(this ItemType itemType)
             => AsStringValue(itemType);
 
         /// <summary>
@@ -456,7 +456,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="loadFlag">LoadFlag to get value from</param>
         /// <returns>String value corresponding to the LoadFlag</returns>
-        public static string FromLoadFlag(this LoadFlag loadFlag)
+        public static string? FromLoadFlag(this LoadFlag loadFlag)
             => AsStringValue(loadFlag);
 
         /// <summary>
@@ -465,7 +465,7 @@ namespace SabreTools.Core.Tools
         /// <param name="gametype">MachineType to get value from</param>
         /// <param name="romCenter">True to use old naming instead</param>
         /// <returns>String value corresponding to the MachineType</returns>
-        public static string FromMachineType(this MachineType gametype, bool old)
+        public static string? FromMachineType(this MachineType gametype, bool old)
             => AsStringValue(gametype, old);
 
         /// <summary>
@@ -474,7 +474,7 @@ namespace SabreTools.Core.Tools
         /// <param name="merging">MergingFlag to get value from</param>
         /// <param name="romCenter">True to use RomCenter naming instead</param>
         /// <returns>String value corresponding to the MergingFlag</returns>
-        public static string FromMergingFlag(this MergingFlag merging, bool romCenter)
+        public static string? FromMergingFlag(this MergingFlag merging, bool romCenter)
             => AsStringValue(merging, romCenter);
 
         /// <summary>
@@ -482,7 +482,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="nodump">NodumpFlag to get value from</param>
         /// <returns>String value corresponding to the NodumpFlag</returns>
-        public static string FromNodumpFlag(this NodumpFlag nodump)
+        public static string? FromNodumpFlag(this NodumpFlag nodump)
             => AsStringValue(nodump);
 
         /// <summary>
@@ -490,7 +490,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="subType">OpenMSXSubType to get value from</param>
         /// <returns>String value corresponding to the OpenMSXSubType</returns>
-        public static string FromOpenMSXSubType(this OpenMSXSubType subType)
+        public static string? FromOpenMSXSubType(this OpenMSXSubType subType)
             => AsStringValue(subType);
 
         /// <summary>
@@ -499,7 +499,7 @@ namespace SabreTools.Core.Tools
         /// <param name="packing">PackingFlag to get value from</param>
         /// <param name="yesno">True to use Yes/No format instead</param>
         /// <returns>String value corresponding to the PackingFlag</returns>
-        public static string FromPackingFlag(this PackingFlag packing, bool yesno)
+        public static string? FromPackingFlag(this PackingFlag packing, bool yesno)
             => AsStringValue(packing, yesno);
 
         /// <summary>
@@ -507,7 +507,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="relation">Relation to get value from</param>
         /// <returns>String value corresponding to the Relation</returns>
-        public static string FromRelation(this Relation relation)
+        public static string? FromRelation(this Relation relation)
             => AsStringValue(relation);
 
         /// <summary>
@@ -515,7 +515,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="runnable">Runnable to get value from</param>
         /// <returns>String value corresponding to the Runnable</returns>
-        public static string FromRunnable(this Runnable runnable)
+        public static string? FromRunnable(this Runnable runnable)
             => AsStringValue(runnable);
 
         /// <summary>
@@ -523,7 +523,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="status">SoftwareListStatus to get value from</param>
         /// <returns>String value corresponding to the SoftwareListStatus</returns>
-        public static string FromSoftwareListStatus(this SoftwareListStatus status)
+        public static string? FromSoftwareListStatus(this SoftwareListStatus status)
             => AsStringValue(status);
 
         /// <summary>
@@ -532,7 +532,7 @@ namespace SabreTools.Core.Tools
         /// <param name="supported">Supported to get value from</param>
         /// <param name="verbose">True to use verbose output, false otherwise</param>
         /// <returns>String value corresponding to the Supported</returns>
-        public static string FromSupported(this Supported supported, bool verbose)
+        public static string? FromSupported(this Supported supported, bool verbose)
             => AsStringValue(supported, verbose);
 
         /// <summary>
@@ -540,7 +540,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="supportStatus">SupportStatus to get value from</param>
         /// <returns>String value corresponding to the SupportStatus</returns>
-        public static string FromSupportStatus(this SupportStatus supportStatus)
+        public static string? FromSupportStatus(this SupportStatus supportStatus)
             => AsStringValue(supportStatus);
 
         /// <summary>
@@ -548,7 +548,7 @@ namespace SabreTools.Core.Tools
         /// </summary>
         /// <param name="yesno">bool? to get value from</param>
         /// <returns>String corresponding to the bool?</returns>
-        public static string FromYesNo(this bool? yesno)
+        public static string? FromYesNo(this bool? yesno)
         {
             return yesno switch
             {
@@ -565,7 +565,7 @@ namespace SabreTools.Core.Tools
         /// <param name="useSecond">True to use the second mapping option, if it exists</param>
         /// <typeparam name="T">Enum type that is expected</typeparam>
         /// <returns>String value representing the input, default on error</returns>
-        internal static string? AsStringValue<T>(T value, bool useSecond = false)
+        internal static string? AsStringValue<T>(T value, bool useSecond = false) where T : notnull
         {
             // Get the mapping dictionary
             var mappings = GenerateToString<T>(useSecond);
@@ -584,7 +584,7 @@ namespace SabreTools.Core.Tools
         /// <param name="useSecond">True to use the second mapping option, if it exists</param>
         /// <typeparam name="T">Enum type that is expected</typeparam>
         /// <returns>Dictionary of enum to string values</returns>
-        internal static Dictionary<T, string> GenerateToString<T>(bool useSecond)
+        internal static Dictionary<T, string> GenerateToString<T>(bool useSecond) where T : notnull
         {
             try
             {
@@ -596,7 +596,7 @@ namespace SabreTools.Core.Tools
                 foreach (T value in values)
                 {
                     // Try to get the mapping attribute
-                    MappingAttribute attr = AttributeHelper<T>.GetAttribute(value);
+                    MappingAttribute? attr = AttributeHelper<T>.GetAttribute(value);
                     if (attr?.Mappings == null || !attr.Mappings.Any())
                         continue;
 
diff --git a/SabreTools.Core/Tools/Hasher.cs b/SabreTools.Core/Tools/Hasher.cs
index 871efcd7..3e91d25e 100644
--- a/SabreTools.Core/Tools/Hasher.cs
+++ b/SabreTools.Core/Tools/Hasher.cs
@@ -12,7 +12,7 @@ namespace SabreTools.Core.Tools
     public class Hasher
     {
         public Hash HashType { get; private set; }
-        private IDisposable _hasher; 
+        private IDisposable? _hasher;
 
         public Hasher(Hash hashType)
         {
@@ -59,7 +59,7 @@ namespace SabreTools.Core.Tools
 
         public void Dispose()
         {
-            _hasher.Dispose();
+            _hasher?.Dispose();
         }
 
         /// <summary>
@@ -67,22 +67,37 @@ namespace SabreTools.Core.Tools
         /// </summary>
         public void Process(byte[] buffer, int size)
         {
-            switch (HashType)
+            if (_hasher == null)
+                return;
+
+            switch (_hasher)
             {
-                case Hash.CRC:
-                    (_hasher as OptimizedCRC.OptimizedCRC).Update(buffer, 0, size);
+                case OptimizedCRC.OptimizedCRC crc:
+                    crc.Update(buffer, 0, size);
                     break;
 
-                case Hash.MD5:
-                case Hash.SHA1:
-                case Hash.SHA256:
-                case Hash.SHA384:
-                case Hash.SHA512:
-                    (_hasher as HashAlgorithm).TransformBlock(buffer, 0, size, null, 0);
+                case MD5 md5:
+                    md5.TransformBlock(buffer, 0, size, null, 0);
                     break;
 
-                case Hash.SpamSum:
-                    (_hasher as SpamSumContext).Update(buffer);
+                case SHA1 sha1:
+                    sha1.TransformBlock(buffer, 0, size, null, 0);
+                    break;
+
+                case SHA256 sha256:
+                    sha256.TransformBlock(buffer, 0, size, null, 0);
+                    break;
+
+                case SHA384 sha384:
+                    sha384.TransformBlock(buffer, 0, size, null, 0);
+                    break;
+
+                case SHA512 sha512:
+                    sha512.TransformBlock(buffer, 0, size, null, 0);
+                    break;
+
+                case SpamSumContext spamSum:
+                    spamSum.Update(buffer);
                     break;
             }
         }
@@ -92,22 +107,37 @@ namespace SabreTools.Core.Tools
         /// </summary>
         public void Terminate()
         {
+            if (_hasher == null)
+                return;
+
             byte[] emptyBuffer = Array.Empty<byte>();
-            switch (HashType)
+            switch (_hasher)
             {
-                case Hash.CRC:
-                    (_hasher as OptimizedCRC.OptimizedCRC).Update(emptyBuffer, 0, 0);
+                case OptimizedCRC.OptimizedCRC crc:
+                    crc.Update(emptyBuffer, 0, 0);
                     break;
 
-                case Hash.MD5:
-                case Hash.SHA1:
-                case Hash.SHA256:
-                case Hash.SHA384:
-                case Hash.SHA512:
-                    (_hasher as HashAlgorithm).TransformFinalBlock(emptyBuffer, 0, 0);
+                case MD5 md5:
+                    md5.TransformFinalBlock(emptyBuffer, 0, 0);
                     break;
 
-                case Hash.SpamSum:
+                case SHA1 sha1:
+                    sha1.TransformFinalBlock(emptyBuffer, 0, 0);
+                    break;
+
+                case SHA256 sha256:
+                    sha256.TransformFinalBlock(emptyBuffer, 0, 0);
+                    break;
+
+                case SHA384 sha384:
+                    sha384.TransformFinalBlock(emptyBuffer, 0, 0);
+                    break;
+
+                case SHA512 sha512:
+                    sha512.TransformFinalBlock(emptyBuffer, 0, 0);
+                    break;
+
+                case SpamSumContext:
                     // No finalization step needed
                     break;
             }
@@ -116,17 +146,17 @@ namespace SabreTools.Core.Tools
         /// <summary>
         /// Get internal hash as a byte array
         /// </summary>
-        public byte[] GetHash()
+        public byte[]? GetHash()
         {
-            return HashType switch
+            return _hasher switch
             {
-                Hash.CRC => BitConverter.GetBytes((_hasher as OptimizedCRC.OptimizedCRC).Value).Reverse().ToArray(),
-                Hash.MD5 => (_hasher as HashAlgorithm).Hash,
-                Hash.SHA1 => (_hasher as HashAlgorithm).Hash,
-                Hash.SHA256 => (_hasher as HashAlgorithm).Hash,
-                Hash.SHA384 => (_hasher as HashAlgorithm).Hash,
-                Hash.SHA512 => (_hasher as HashAlgorithm).Hash,
-                Hash.SpamSum => (_hasher as SpamSumContext).Final(),
+                OptimizedCRC.OptimizedCRC crc => BitConverter.GetBytes(crc.Value).Reverse().ToArray(),
+                MD5 md5 => md5.Hash,
+                SHA1 sha1 => sha1.Hash,
+                SHA256 sha256 => sha256.Hash,
+                SHA384 sha384 => sha384.Hash,
+                SHA512 sha512 => sha512.Hash,
+                SpamSumContext spamSum => spamSum.Final(),
                 _ => null,
             };
         }
diff --git a/SabreTools.Core/Tools/OptimizedCRC.cs b/SabreTools.Core/Tools/OptimizedCRC.cs
index 160a7757..700800be 100644
--- a/SabreTools.Core/Tools/OptimizedCRC.cs
+++ b/SabreTools.Core/Tools/OptimizedCRC.cs
@@ -142,7 +142,7 @@ namespace OptimizedCRC
 
         static public int Compute(ArraySegment<byte> block)
         {
-            return Compute(block.Array, block.Offset, block.Count);
+            return Compute(block.Array!, block.Offset, block.Count);
         }
 
         public void Dispose()
diff --git a/SabreTools.Core/Tools/Utilities.cs b/SabreTools.Core/Tools/Utilities.cs
index 95d30c10..0940b17f 100644
--- a/SabreTools.Core/Tools/Utilities.cs
+++ b/SabreTools.Core/Tools/Utilities.cs
@@ -16,7 +16,7 @@ namespace SabreTools.Core.Tools
         /// <param name="bytes">Byte array to convert</param>
         /// <returns>Hex string representing the byte array</returns>
         /// <link>http://stackoverflow.com/questions/311165/how-do-you-convert-byte-array-to-hexadecimal-string-and-vice-versa</link>
-        public static string ByteArrayToString(byte[] bytes)
+        public static string? ByteArrayToString(byte[]? bytes)
         {
             // If we get null in, we send null out
             if (bytes == null)
@@ -39,10 +39,10 @@ namespace SabreTools.Core.Tools
         /// <param name="hex">Hex string to convert</param>
         /// <returns>Byte array represenging the hex string</returns>
         /// <link>http://stackoverflow.com/questions/311165/how-do-you-convert-byte-array-to-hexadecimal-string-and-vice-versa</link>
-        public static byte[] StringToByteArray(string hex)
+        public static byte[]? StringToByteArray(string? hex)
         {
             // If we get null in, we send null out
-            if (hex == null)
+            if (string.IsNullOrWhiteSpace(hex))
                 return null;
 
             try
@@ -102,7 +102,7 @@ namespace SabreTools.Core.Tools
         /// <param name="hash">SHA-1 hash to get the path for</param>
         /// <param name="depth">Positive value representing the depth of the depot</param>
         /// <returns>Subfolder path for the given hash</returns>
-        public static string GetDepotPath(string hash, int depth)
+        public static string? GetDepotPath(string? hash, int depth)
         {
             // If the hash is null or empty, then we return null
             if (string.IsNullOrEmpty(hash))
diff --git a/SabreTools.DatFiles/DatFile.cs b/SabreTools.DatFiles/DatFile.cs
index 8af548ff..7fc9e370 100644
--- a/SabreTools.DatFiles/DatFile.cs
+++ b/SabreTools.DatFiles/DatFile.cs
@@ -397,7 +397,7 @@ namespace SabreTools.DatFiles
                 Header.UseRomName = true;
 
             // Get the name to update
-            string name = (Header.UseRomName ? item.GetName() : item.Machine.Name) ?? string.Empty;
+            string? name = (Header.UseRomName ? item.GetName() : item.Machine.Name) ?? string.Empty;
 
             // Create the proper Prefix and Postfix
             string pre = CreatePrefixPostfix(item, true);
@@ -411,7 +411,7 @@ namespace SabreTools.DatFiles
                     // We can only write out if there's a SHA-1
                     if (!string.IsNullOrWhiteSpace(disk.SHA1))
                     {
-                        name = Utilities.GetDepotPath(disk.SHA1, Header.OutputDepot.Depth).Replace('\\', '/');
+                        name = Utilities.GetDepotPath(disk.SHA1, Header.OutputDepot.Depth)?.Replace('\\', '/');
                         item.SetName($"{pre}{name}{post}");
                     }
                 }
@@ -420,7 +420,7 @@ namespace SabreTools.DatFiles
                     // We can only write out if there's a SHA-1
                     if (!string.IsNullOrWhiteSpace(media.SHA1))
                     {
-                        name = Utilities.GetDepotPath(media.SHA1, Header.OutputDepot.Depth).Replace('\\', '/');
+                        name = Utilities.GetDepotPath(media.SHA1, Header.OutputDepot.Depth)?.Replace('\\', '/');
                         item.SetName($"{pre}{name}{post}");
                     }
                 }
@@ -429,7 +429,7 @@ namespace SabreTools.DatFiles
                     // We can only write out if there's a SHA-1
                     if (!string.IsNullOrWhiteSpace(rom.SHA1))
                     {
-                        name = Utilities.GetDepotPath(rom.SHA1, Header.OutputDepot.Depth).Replace('\\', '/');
+                        name = Utilities.GetDepotPath(rom.SHA1, Header.OutputDepot.Depth)?.Replace('\\', '/');
                         item.SetName($"{pre}{name}{post}");
                     }
                 }
diff --git a/SabreTools.DatFiles/Formats/ClrMamePro.Reader.cs b/SabreTools.DatFiles/Formats/ClrMamePro.Reader.cs
index ae24b3d0..a8d9e449 100644
--- a/SabreTools.DatFiles/Formats/ClrMamePro.Reader.cs
+++ b/SabreTools.DatFiles/Formats/ClrMamePro.Reader.cs
@@ -60,11 +60,11 @@ namespace SabreTools.DatFiles.Formats
             Header.HeaderSkipper ??= cmp.Header;
             Header.Type ??= cmp.Type;
             if (Header.ForceMerging == MergingFlag.None)
-                Header.ForceMerging = cmp.ForceMerging.AsMergingFlag();
+                Header.ForceMerging = cmp.ForceMerging?.AsMergingFlag() ?? MergingFlag.None;
             if (Header.ForcePacking == PackingFlag.None)
-                Header.ForcePacking = cmp.ForceZipping.AsPackingFlag();
+                Header.ForcePacking = cmp.ForceZipping?.AsPackingFlag() ?? PackingFlag.None;
             if (Header.ForcePacking == PackingFlag.None)
-                Header.ForcePacking = cmp.ForcePacking.AsPackingFlag();
+                Header.ForcePacking = cmp.ForcePacking?.AsPackingFlag() ?? PackingFlag.None;
 
             // Handle implied SuperDAT
             if (cmp.Name?.Contains(" - SuperDAT") == true && keep)
diff --git a/SabreTools.DatFiles/ItemDictionary.cs b/SabreTools.DatFiles/ItemDictionary.cs
index 29767dd7..2092a6c4 100644
--- a/SabreTools.DatFiles/ItemDictionary.cs
+++ b/SabreTools.DatFiles/ItemDictionary.cs
@@ -1040,7 +1040,9 @@ namespace SabreTools.DatFiles
                 Parallel.ForEach(keys, Globals.ParallelOptions, key =>
                 {
                     // Get the possibly unsorted list
-                    ConcurrentList<DatItem> sortedlist = this[key].ToConcurrentList();
+                    ConcurrentList<DatItem>? sortedlist = this[key]?.ToConcurrentList();
+                    if (sortedlist == null)
+                        return;
 
                     // Sort the list of items to be consistent
                     DatItem.Sort(ref sortedlist, false);
diff --git a/SabreTools.DatFiles/ItemDictionaryDB.cs b/SabreTools.DatFiles/ItemDictionaryDB.cs
index 35d4133d..c42b4b19 100644
--- a/SabreTools.DatFiles/ItemDictionaryDB.cs
+++ b/SabreTools.DatFiles/ItemDictionaryDB.cs
@@ -1240,7 +1240,9 @@ CREATE TABLE IF NOT EXISTS groups (
                 Parallel.ForEach(keys, Globals.ParallelOptions, key =>
                 {
                     // Get the possibly unsorted list
-                    ConcurrentList<DatItem> sortedlist = this[key].ToConcurrentList();
+                    ConcurrentList<DatItem>? sortedlist = this[key]?.ToConcurrentList();
+                    if (sortedlist == null)
+                        return;
 
                     // Sort the list of items to be consistent
                     DatItem.Sort(ref sortedlist, false);
diff --git a/SabreTools.Filter/FilterObject.cs b/SabreTools.Filter/FilterObject.cs
index 57edd7ec..1679937f 100644
--- a/SabreTools.Filter/FilterObject.cs
+++ b/SabreTools.Filter/FilterObject.cs
@@ -353,10 +353,8 @@ namespace SabreTools.Filter
 
             return value.ToLowerInvariant() switch
             {
-                "true" => true,
-                "yes" => true,
-                "false" => false,
-                "no" => false,
+                "true" or "yes" => true,
+                "false" or "no" => false,
                 _ => null,
             };
         }
diff --git a/SabreTools.Models/Internal/DictionaryBase.cs b/SabreTools.Models/Internal/DictionaryBase.cs
index c0909aac..9424042e 100644
--- a/SabreTools.Models/Internal/DictionaryBase.cs
+++ b/SabreTools.Models/Internal/DictionaryBase.cs
@@ -32,10 +32,8 @@ namespace SabreTools.Models.Internal
             string? asString = Read<string>(key);
             return asString?.ToLowerInvariant() switch
             {
-                "true" => true,
-                "yes" => true,
-                "false" => false,
-                "no" => false,
+                "true" or "yes" => true,
+                "false" or "no" => false,
                 _ => null,
             };
         }