diff --git a/include/class.config.php b/include/class.config.php
index 9fbddc5ac56c2912a898ab8d17acec8083cbf8f8..693034e4e94481207ebea66548acdfa04b292c11 100644
--- a/include/class.config.php
+++ b/include/class.config.php
@@ -1370,7 +1370,7 @@ class OsticketConfig extends Config {
         if (isset($vars['delete-logo']))
             foreach ($vars['delete-logo'] as $id)
                 if (($vars['selected-logo'] != $id)
-                        && ($f = AttachmentFile::lookup($id)))
+                        && ($f = AttachmentFile::lookup((int) $id)))
                     $f->delete();
 
         return $this->updateAll(array(