diff --git a/src/Site/Lib/Auth.php b/src/Site/Lib/Auth.php
index 61ee4f1..4f6f80e 100644
--- a/src/Site/Lib/Auth.php
+++ b/src/Site/Lib/Auth.php
@@ -271,6 +271,7 @@ class Auth {
         break;
       }
     }
+    if (!isset($matches[0])) return 0;
     $id = (int)preg_replace('/^(.*?)\.(.*?)$/', "$1", str_replace($this->dataDir, '', $matches[0]));
 
     return $id;