diff --git a/htdocs/user/class/user.class.php b/htdocs/user/class/user.class.php
index 8e3e49fe2be..2f60be4b05d 100644
--- a/htdocs/user/class/user.class.php
+++ b/htdocs/user/class/user.class.php
@@ -897,7 +897,7 @@ class User extends CommonObject
 					} else {
 						if (empty($this->rights->$module->$perms)) $this->nb_rights++;
 						// if we have already define a subperm like this $this->rights->$module->level1->level2 with llx_user_rights, we don't want override level1 because the level2 can be not define on user group
-						if (!is_object($this->rights->$module->$perms)) $this->rights->$module->$perms = 1;
+						if (!isset($this->rights->$module->$perms) || !is_object($this->rights->$module->$perms)) $this->rights->$module->$perms = 1;
 					}
 				}
 				$i++;