diff --git a/SabreTools.Serialization/Models/MSDOS/Constants.cs b/SabreTools.Serialization/Models/MSDOS/Constants.cs
index f817b7bc..91f139e5 100644
--- a/SabreTools.Serialization/Models/MSDOS/Constants.cs
+++ b/SabreTools.Serialization/Models/MSDOS/Constants.cs
@@ -8,4 +8,4 @@ namespace SabreTools.Data.Models.MSDOS
 
         public const ushort SignatureUInt16 = 0x5a4d;
     }
-}
\ No newline at end of file
+}
diff --git a/SabreTools.Serialization/Models/MSDOS/Executable.cs b/SabreTools.Serialization/Models/MSDOS/Executable.cs
index 3ce63170..d573fa75 100644
--- a/SabreTools.Serialization/Models/MSDOS/Executable.cs
+++ b/SabreTools.Serialization/Models/MSDOS/Executable.cs
@@ -14,7 +14,7 @@ namespace SabreTools.Data.Models.MSDOS
         /// <summary>
         /// MS-DOS executable header
         /// </summary>
-        public ExecutableHeader? Header { get; set; }
+        public ExecutableHeader Header { get; set; }
 
         /// <summary>
         /// After loading the executable into memory, the program loader goes through
@@ -24,6 +24,6 @@ namespace SabreTools.Data.Models.MSDOS
         /// make the loader add start segment address to the value at offset
         /// 1*0x10+0x1A=0x2A within the program data.
         /// </summary>
-        public RelocationEntry[]? RelocationTable { get; set; }
+        public RelocationEntry[] RelocationTable { get; set; }
     }
 }
diff --git a/SabreTools.Serialization/Models/MSDOS/ExecutableHeader.cs b/SabreTools.Serialization/Models/MSDOS/ExecutableHeader.cs
index 95255921..8f3a3ef4 100644
--- a/SabreTools.Serialization/Models/MSDOS/ExecutableHeader.cs
+++ b/SabreTools.Serialization/Models/MSDOS/ExecutableHeader.cs
@@ -18,7 +18,7 @@ namespace SabreTools.Data.Models.MSDOS
         /// </summary>
         /// <remarks>15 bytes</remarks>
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 2)]
-        public string? Magic;
+        public string Magic;
 
         /// <summary>
         /// Number of bytes in the last page.
@@ -104,7 +104,7 @@ namespace SabreTools.Data.Models.MSDOS
         /// </summary>
         /// <remarks>4 entries/remarks>
         [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
-        public ushort[]? Reserved1;
+        public ushort[] Reserved1 = new ushort[4];
 
         /// <summary>
         /// Defined by name but no other information is given; typically zeroes
@@ -121,7 +121,7 @@ namespace SabreTools.Data.Models.MSDOS
         /// </summary>
         /// <remarks>10 entries/remarks>
         [MarshalAs(UnmanagedType.ByValArray, SizeConst = 10)]
-        public ushort[]? Reserved2;
+        public ushort[] Reserved2 = new ushort[10];
 
         /// <summary>
         /// Starting address of the PE header
diff --git a/SabreTools.Serialization/WrapperFactory.cs b/SabreTools.Serialization/WrapperFactory.cs
index 5517144a..9700abaa 100644
--- a/SabreTools.Serialization/WrapperFactory.cs
+++ b/SabreTools.Serialization/WrapperFactory.cs
@@ -86,7 +86,7 @@ namespace SabreTools.Serialization
                 return null;
 
             // Check for a valid new executable address
-            if (msdos.Model.Header?.NewExeHeaderAddr == null || initialOffset + msdos.Model.Header.NewExeHeaderAddr >= stream.Length)
+            if (initialOffset + msdos.Model.Header.NewExeHeaderAddr >= stream.Length)
                 return wrapper;
 
             // Try to read the executable info
@@ -833,7 +833,7 @@ namespace SabreTools.Serialization
                 return WrapperType.XZP;
 
             #endregion
-            
+
             #region ZSTD
 
             if (magic.StartsWith([null, 0xB5, 0x2F, 0xFD]))
diff --git a/SabreTools.Serialization/Wrappers/MSDOS.Printing.cs b/SabreTools.Serialization/Wrappers/MSDOS.Printing.cs
index c44b6e09..66660f9d 100644
--- a/SabreTools.Serialization/Wrappers/MSDOS.Printing.cs
+++ b/SabreTools.Serialization/Wrappers/MSDOS.Printing.cs
@@ -50,11 +50,11 @@ namespace SabreTools.Serialization.Wrappers
             builder.AppendLine();
         }
 
-        private static void Print(StringBuilder builder, RelocationEntry[]? entries)
+        private static void Print(StringBuilder builder, RelocationEntry[] entries)
         {
             builder.AppendLine("  Relocation Table Information:");
             builder.AppendLine("  -------------------------");
-            if (entries == null || entries.Length == 0)
+            if (entries.Length == 0)
             {
                 builder.AppendLine("  No relocation table items");
                 builder.AppendLine();