diff --git a/Source/Core/General/MapManager.cs b/Source/Core/General/MapManager.cs
index 39781a348503332222050f9728889df24f065b41..a3b4cac894efdbb99c10b6568904bb3dd99abdba 100644
--- a/Source/Core/General/MapManager.cs
+++ b/Source/Core/General/MapManager.cs
@@ -905,7 +905,7 @@ namespace CodeImp.DoomBuilder
 					if(purpose == SavePurpose.IntoFile) 
 					{
 						WAD wad = new WAD(newfilepathname, true);
-						int mapindex = wad.FindLumpIndex(origmapname);
+                        int mapindex = FindAndRemoveMap(wad, origmapname, false);
 						wad.Dispose();
 
 						if(mapindex != -1 && MessageBox.Show(General.MainWindow, "Target file already contains map '" + origmapname + "'\nDo you want to replace it?", "Map already exists!", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) == DialogResult.No)