diff --git a/hack/add-license.sh b/hack/add-license.sh
index ca1da5112..18af2fe09 100755
--- a/hack/add-license.sh
+++ b/hack/add-license.sh
@@ -36,4 +36,9 @@ if [[ $mode == "check" ]]; then
   args+=(-check)
 fi
 
-addlicense "${args[@]}" .
+if  ! addlicense "${args[@]}" .  ; then
+  set +x
+  echo -e "\n------------------------------------------------------------------------"
+  echo "Error: license missing in one or more files. Run \`$0 run\` to update them."
+  exit 1
+fi