diff --git a/apps/user_ldap/lib/connection.php b/apps/user_ldap/lib/connection.php
index 0bf2efe35afc387cc6437ea872c58c3e5f9521b3..7ed3f3afe909bd5d06551576f697a7db28f5e5f7 100644
--- a/apps/user_ldap/lib/connection.php
+++ b/apps/user_ldap/lib/connection.php
@@ -295,7 +295,8 @@ class Connection {
 
 		foreach($config as $parameter => $value) {
 			if(($parameter == 'homeFolderNamingRule'
-				|| $params[$parameter] == 'homeFolderNamingRule')
+				|| (isset($params[$parameter])
+					&& $params[$parameter] == 'homeFolderNamingRule'))
 				&& !empty($value)) {
 				$value = 'attr:'.$value;
 			}