diff --git a/DATabase/Generate.cs b/DATabase/Generate.cs
index e6322131..1c3e199e 100644
--- a/DATabase/Generate.cs
+++ b/DATabase/Generate.cs
@@ -241,13 +241,10 @@ JOIN checksums
 	(!srcmerged && !sysmerged ? " AND" : "") +
 	(!sysmerged ? " systems.id=" + _system : "") + "\n" +
 	(sysmerged && srcmerged ? "\nWHERE" : " AND") +
-" files.id IN ( SELECT file from checksums WHERE file IN (" +
-" SELECT file FROM checksums WHERE file IN (" +
-" SELECT file FROM checksums" +
-	(merged ? "\nGROUP BY size, sha1" : "") + " )" +
-	(merged ? "\nGROUP BY size, md5" : "") + " )" +
-	(merged ? "\nGROUP BY size, crc" : "") + " )" +
-  (merged ? "\nGROUP BY checksums.size, checksums.md5, checksums.sha1" : "") +
+"\n files.id IN ( SELECT checksums.file FROM checksums JOIN files ON checksums.file=files.id WHERE files.type='rom'" +
+	(merged ? "\nGROUP BY checksums.size, checksums.crc" : "") + " )" +
+"\n OR files.id IN ( SELECT checksums.file FROM checksums JOIN files ON checksums.file=files.id WHERE files.type='disk'" +
+	(merged ? "\nGROUP BY checksums.sha1" : "") + " )" +
 "\nORDER BY systems.id, sources.id, games.name, files.name";
 
 			using (SQLiteConnection dbc = new SQLiteConnection(_connectionString))