diff --git a/framework/ActiveSync/lib/Horde/ActiveSync/State/Mongo.php b/framework/ActiveSync/lib/Horde/ActiveSync/State/Mongo.php
index 18b55d3367c..d75359898d2 100644
--- a/framework/ActiveSync/lib/Horde/ActiveSync/State/Mongo.php
+++ b/framework/ActiveSync/lib/Horde/ActiveSync/State/Mongo.php
@@ -1190,8 +1190,9 @@ protected function _isPIMChangeQuery($id, $flag, $field)
             'sync_devid' => $this->_deviceInfo->id,
             'sync_user' => $this->_deviceInfo->user,
             'sync_folderid' => $this->_collection['id'],
-            'message_uid' => $id,
+            'message_uid' => "$id",
         );
+
         try {
             $result = $this->_db->mailmap->findOne(
                 $query,