diff --git a/git-hooks/gerrit-bot-cleanup b/git-hooks/gerrit-bot-cleanup
index 97cfde30455d4b6f517aac24cfb30ba8e014b75a..ca8da11950255f8badbb00b26122efdf92398104 100755
--- a/git-hooks/gerrit-bot-cleanup
+++ b/git-hooks/gerrit-bot-cleanup
@@ -20,6 +20,8 @@ if test -z "$root"; then
 fi
 cd "$root" || exit
 find -name '*.git' -type d -prune | while read dir; do (
+    # use "git config --global gc.packrefs notbare" to make sure this works
+    test -d $dir/refs/changes || exit
     echo "Entering $dir ..."
     cd "$dir" || exit
     find refs/changes -mindepth 1 -mtime +10 -delete