diff --git a/rerere.c b/rerere.c
index d55aa8a01b..fd65a93873 100644
--- a/rerere.c
+++ b/rerere.c
@@ -667,6 +667,8 @@ int rerere_forget(struct pathspec *pathspec)
 		return error("Could not read index");
 
 	fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
+	if (fd < 0)
+		return 0;
 
 	unmerge_cache(pathspec);
 	find_conflict(&conflict);