diff --git a/lib/Sabre/DAV/Locks/Plugin.php b/lib/Sabre/DAV/Locks/Plugin.php
index bbbb533983..931df889db 100644
--- a/lib/Sabre/DAV/Locks/Plugin.php
+++ b/lib/Sabre/DAV/Locks/Plugin.php
@@ -374,6 +374,7 @@ public function lockNode($uri,Sabre_DAV_Locks_LockInfo $lockInfo) {
             // In case the node didn't exist, this could be a lock-null request
         }
         if ($this->locksBackend) return $this->locksBackend->lock($uri,$lockInfo);
+        throw new Sabre_DAV_Exception_NotImplemented('Locking support not implemented for this resource. No Locking backend was found');
 
     }