diff --git a/DATabase/MergeDiff.cs b/DATabase/MergeDiff.cs
index b133965e..1b935bc1 100644
--- a/DATabase/MergeDiff.cs
+++ b/DATabase/MergeDiff.cs
@@ -127,7 +127,7 @@ namespace SabreTools
 				{
 					datHeaders.Add(new DatData
 					{
-						FileName = Path.GetFullPath(userData.FileName),
+						FileName = userData.FileName,
 						Name = userData.Name,
 						Description = userData.Description,
 						Version = userData.Version,
@@ -148,7 +148,7 @@ namespace SabreTools
 					userData.Category = "";
 					userData.Author = "";
 					userData.ForcePacking = ForcePacking.None;
-					userData.OutputFormat = OutputFormat.Xml;
+					userData.OutputFormat = OutputFormat.None;
 					userData.Type = "";
 				}
 			}
diff --git a/SabreHelper/Data/Enums.cs b/SabreHelper/Data/Enums.cs
index 282b64b1..4a546124 100644
--- a/SabreHelper/Data/Enums.cs
+++ b/SabreHelper/Data/Enums.cs
@@ -99,7 +99,8 @@ namespace SabreTools.Helper
 	/// </summary>
 	public enum OutputFormat
 	{
-		Xml = 0,
+		None = 0,
+		Xml,
 		ClrMamePro,
 		RomCenter,
 		DOSCenter,
diff --git a/SabreHelper/RomManipulation.cs b/SabreHelper/RomManipulation.cs
index 783a6d61..913b3d32 100644
--- a/SabreHelper/RomManipulation.cs
+++ b/SabreHelper/RomManipulation.cs
@@ -100,6 +100,12 @@ namespace SabreTools.Helper
 				datdata.FileName = Path.GetFileNameWithoutExtension(filename);
 			}
 
+			// If the output type isn't set already, get the internal output type
+			if (datdata.OutputFormat == OutputFormat.None)
+			{
+				datdata.OutputFormat = GetOutputFormat(filename);
+			}
+
 			// Make sure there's a dictionary to read to
 			if (datdata.Roms == null)
 			{