diff --git a/SabreTools.Helper/Tools/ArchiveTools.cs b/SabreTools.Helper/Tools/ArchiveTools.cs
index 962c6811..ab3c005f 100644
--- a/SabreTools.Helper/Tools/ArchiveTools.cs
+++ b/SabreTools.Helper/Tools/ArchiveTools.cs
@@ -1102,6 +1102,13 @@ namespace SabreTools.Helper.Tools
 		public static bool WriteTAR(List<string> inputFiles, string outDir, List<Rom> roms, Logger logger, bool date = false)
 		{
 			bool success = false;
+			string tempFile = Path.GetTempFileName();
+
+			// If either list of roms is null or empty, return
+			if (inputFiles == null || roms == null || inputFiles.Count == 0 || roms.Count == 0)
+			{
+				return success;
+			}
 
 			// If the number of inputs is less than the number of available roms, return
 			if (inputFiles.Count < roms.Count)
@@ -1122,8 +1129,8 @@ namespace SabreTools.Helper.Tools
 			string archiveFileName = Path.Combine(outDir, Style.RemovePathUnsafeCharacters(roms[0].Machine.Name) + (roms[0].Machine.Name.EndsWith(".tar") ? "" : ".tar"));
 
 			// Set internal variables
-			Stream tarstream = new MemoryStream();
-			TarArchive tarchive = TarArchive.Create();
+			TarArchive oldTarFile = TarArchive.Create();
+			TarArchive tarFile = TarArchive.Create();
 
 			try
 			{
@@ -1133,42 +1140,120 @@ namespace SabreTools.Helper.Tools
 					Directory.CreateDirectory(Path.GetDirectoryName(archiveFileName));
 				}
 
-				// We can only overwrite at this point, sorry
-				tarstream = File.Open(archiveFileName, FileMode.Create, FileAccess.Write);
-
-				// Map all inputs to index
-				Dictionary<string, int> inputIndexMap = new Dictionary<string, int>();
-				for (int i = 0; i < inputFiles.Count; i++)
+				// If the archive doesn't exist, create it and put the single file
+				if (!File.Exists(archiveFileName))
 				{
-					inputIndexMap.Add(roms[i].Name.Replace('\\', '/'), i);
+					// Map all inputs to index
+					Dictionary<string, int> inputIndexMap = new Dictionary<string, int>();
+					for (int i = 0; i < inputFiles.Count; i++)
+					{
+						inputIndexMap.Add(roms[i].Name.Replace('\\', '/'), i);
+					}
+
+					// Sort the keys in TZIP order
+					List<string> keys = inputIndexMap.Keys.ToList();
+					keys.Sort(ZipFile.TorrentZipStringCompare);
+
+					// Now add all of the files in order
+					foreach (string key in keys)
+					{
+						// Get the index mapped to the key
+						int index = inputIndexMap[key];
+
+						// Copy the input stream to the output
+						tarFile.AddEntry(roms[index].Name, inputFiles[index]);
+					}
 				}
 
-				// Sort the keys in TZIP order
-				List<string> keys = inputIndexMap.Keys.ToList();
-				keys.Sort(ZipFile.TorrentZipStringCompare);
-
-				// Now add each of the files
-				foreach (string key in keys)
+				// Otherwise, sort the input files and write out in the correct order
+				else
 				{
-					int index = inputIndexMap[key];
-					tarchive.AddEntry(key, inputFiles[index]);
+					// Open the old archive for reading
+					oldTarFile = TarArchive.Open(archiveFileName);
+
+					// Get a list of all current entries
+					List<string> entries = oldTarFile.Entries.Select(i => i.Key).ToList();
+
+					// Map all inputs to index
+					Dictionary<string, int> inputIndexMap = new Dictionary<string, int>();
+					for (int i = 0; i < inputFiles.Count; i++)
+					{
+						// If the old one contains the new file, then just skip out
+						if (entries.Contains(roms[i].Name.Replace('\\', '/')))
+						{
+							continue;
+						}
+
+						inputIndexMap.Add(roms[i].Name.Replace('\\', '/'), -(i + 1));
+					}
+
+					// Then add all of the old entries to it too
+					for (int i = 0; i < entries.Count; i++)
+					{
+						inputIndexMap.Add(entries[i], i);
+					}
+
+					// If the number of entries is the same as the old archive, skip out
+					if (inputIndexMap.Keys.Count <= entries.Count)
+					{
+						success = true;
+						return success;
+					}
+
+					// Get the order for the entries with the new file
+					List<string> keys = inputIndexMap.Keys.ToList();
+					keys.Sort(ZipFile.TorrentZipStringCompare);
+
+					// Copy over all files to the new archive
+					foreach (string key in keys)
+					{
+						// Get the index mapped to the key
+						int index = inputIndexMap[key];
+
+						// If we have the input file, add it now
+						if (index < 0)
+						{
+							// Copy the input file to the output
+							tarFile.AddEntry(roms[-index - 1].Name, inputFiles[-index - 1]);
+						}
+
+						// Otherwise, copy the file from the old archive
+						else
+						{
+							// Get the stream from the original archive
+							string tempEntry = Path.GetTempFileName();
+							oldTarFile.Entries.Where(e => e.Key == key).ToList()[0].WriteToFile(tempEntry);
+
+							// Copy the input stream to the output
+							tarFile.AddEntry(key, tempEntry);
+						}
+					}
 				}
 
-				tarchive.SaveTo(tarstream, new WriterOptions(CompressionType.None));
+				// Close the output tar file
+				tarFile.SaveTo(tempFile, new WriterOptions(CompressionType.None));
+
 				success = true;
 			}
 			catch (Exception ex)
 			{
+				Console.WriteLine(ex);
 				success = false;
-				logger.Error(ex.ToString());
 			}
 			finally
 			{
-				tarstream?.Dispose();
-				tarchive?.Dispose();
+				tarFile.Dispose();
+				oldTarFile.Dispose();
 			}
 
-			return success;
+			// If the old file exists, delete it and replace
+			if (File.Exists(archiveFileName))
+			{
+				File.Delete(archiveFileName);
+			}
+			File.Move(tempFile, archiveFileName);
+
+			return true;
 		}
 
 		/// <summary>