diff --git a/DATabase/MergeDiff.cs b/DATabase/MergeDiff.cs
index 19bea00d..3c730d88 100644
--- a/DATabase/MergeDiff.cs
+++ b/DATabase/MergeDiff.cs
@@ -113,6 +113,7 @@ namespace SabreTools
 				_logger.Log("Adding DAT: " + input);
 				RomManipulation.Parse2(input, 0, 0, _dedup, dbc, _logger);
 
+				/*
 				List<RomData> B = RomManipulation.Parse(input, 0, 0, _logger);
 				if (_diff)
 				{
@@ -122,6 +123,7 @@ namespace SabreTools
 				{
 					A.AddRange(B);
 				}
+				*/
 			}
 
 			// Until I find a way to output the roms from the db, here's just a count of the items in it
@@ -129,7 +131,8 @@ namespace SabreTools
 			{
 				_logger.Log("Total number of lines in database: " + slc.ExecuteScalar());
 			}
-			Output.WriteToDat2(_name + "-db", _desc + "-db", _version, _date, _cat, _author, _forceunpack, _old, "", dbc, _logger);
+			Output.WriteToDat2(_name + "-db", _desc + "-db", _version, _date, _cat, _author, _forceunpack, _old, _diff, "", dbc, _logger);
+
 			dbc.Close();
 
 			// If we're in Alldiff mode, we can only use the first 2 inputs
@@ -150,6 +153,7 @@ namespace SabreTools
 				Output.WriteToDat(_name + "-inboth", _desc + "-inboth", _version, _date, _cat, _author, _forceunpack, _old, "", BothAB, _logger);
 			}
 
+			/*
 			// If we want a merged list, send it for merging before outputting
 			if (_dedup)
 			{
@@ -161,6 +165,7 @@ namespace SabreTools
 
 			// Now write the file out
 			Output.WriteToDat(_name, _desc, _version, _date, _cat, _author, _forceunpack, _old, "", A, _logger);
+			*/
 
 			return true;
 		}
diff --git a/SabreHelper/Output.cs b/SabreHelper/Output.cs
index fb68e0aa..b4f87d1b 100644
--- a/SabreHelper/Output.cs
+++ b/SabreHelper/Output.cs
@@ -139,11 +139,13 @@ namespace SabreTools.Helper
 		/// <param name="author">DAT author</param>
 		/// <param name="forceunpack">Force all sets to be unzipped</param>
 		/// <param name="old">Set output mode to old-style DAT</param>
+		/// <param name="diff">Only output files that don't have dupes</param>
 		/// <param name="outDir">Set the output directory</param>
 		/// <param name="dbc">Database connection representing the roms to be written</param>
 		/// <param name="logger">Logger object for console and/or file output</param>
 		/// <returns>Tru if the DAT was written correctly, false otherwise</returns>
-		public static bool WriteToDat2(string name, string description, string version, string date, string category, string author, bool forceunpack, bool old, string outDir, SqliteConnection dbc, Logger logger)
+		public static bool WriteToDat2(string name, string description, string version, string date, string category,
+			string author, bool forceunpack, bool old, bool diff, string outDir, SqliteConnection dbc, Logger logger)
 		{
 			// If it's empty, use the current folder
 			if (outDir.Trim() == "")
@@ -193,7 +195,8 @@ namespace SabreTools.Helper
 
 				// Write out each of the machines and roms
 				string lastgame = "";
-				using (SqliteDataReader sldr = (new SqliteCommand("SELECT * FROM roms ORDER BY game, name", dbc).ExecuteReader()))
+				string query = "SELECT * FROM roms" + (diff ? " WHERE dupe='false'" : "") + " ORDER BY game, name";
+				using (SqliteDataReader sldr = (new SqliteCommand(query, dbc).ExecuteReader()))
 				{
 					while (sldr.Read())
 					{