diff --git a/library/HTMLPurifier/DefinitionCache/Serializer.php b/library/HTMLPurifier/DefinitionCache/Serializer.php
index bfad967fb..9f69dbbff 100644
--- a/library/HTMLPurifier/DefinitionCache/Serializer.php
+++ b/library/HTMLPurifier/DefinitionCache/Serializer.php
@@ -232,7 +232,7 @@ private function _prepareDir($config)
                 trigger_error(
                     'Base directory ' . $base . ' does not exist,
                     please create or change using %Cache.SerializerPath',
-                    E_USER_WARNING
+                    E_USER_WARNING %Cache.SerializerPath
                 );
                 return false;
             } elseif (!$this->_testPermissions($base, $chmod)) {