diff --git a/inc/drivers_ldap.php b/inc/drivers_ldap.php
index 909a1465..a462a8b7 100644
--- a/inc/drivers_ldap.php
+++ b/inc/drivers_ldap.php
@@ -651,7 +651,8 @@ function sync_LDAP_groups(){
     }
 
     foreach ( $groups_to_sync_members as $group ) {
-      $db_members = is_array( $db_group_members[$group] )
+      $db_members = isset($db_group_members[$group])
+          && is_array($db_group_members[$group])
           ? array_values( $db_group_members[$group] )
           : array();
       $ldap_members = isset ( $ldap_groups_info[$group][$member_field] )