diff --git a/mkclean/regression/mkcleanreg.py b/mkclean/regression/mkcleanreg.py
index 677b25c4..b7ca80b0 100755
--- a/mkclean/regression/mkcleanreg.py
+++ b/mkclean/regression/mkcleanreg.py
@@ -115,6 +115,7 @@ def main():
             hash = values[1]
             testFile(args, i, src_file, mkclean_options, filesize, hash)
             i = i+1
+    return 0
 
 if __name__ == "__main__":
     exit(main())