diff --git a/loopback/server/boot/storage.js b/loopback/server/boot/storage.js
index a2434a5e4..d34804059 100644
--- a/loopback/server/boot/storage.js
+++ b/loopback/server/boot/storage.js
@@ -13,6 +13,6 @@ module.exports = app => {
     };
 
     storageConnector.getPathHash = function(id) {
-        return md5(id).substring(0, 3);
+        return md5(id.toString()).substring(0, 3);
     };
 };