diff --git a/Makefile b/Makefile
index 040a8042fe..ad1f392d9e 100644
--- a/Makefile
+++ b/Makefile
@@ -128,6 +128,7 @@ macosx.app:
 		Factor.app/Contents/MacOS/Factor
 
 macosx.dmg:
+	rm $(DISK_IMAGE)
 	rm -rf $(DISK_IMAGE_DIR)
 	mkdir $(DISK_IMAGE_DIR)
 	cp -R $(BUNDLE) $(DISK_IMAGE_DIR)/$(BUNDLE)