diff --git a/openerp/addons/base/res/res_user.py b/openerp/addons/base/res/res_user.py
index beac24d44be..6582226c2d5 100644
--- a/openerp/addons/base/res/res_user.py
+++ b/openerp/addons/base/res/res_user.py
@@ -593,6 +593,8 @@ class users_implied(osv.osv):
         return user_id
 
     def write(self, cr, uid, ids, values, context=None):
+        if not isinstance(ids,list):
+            ids = [ids]
         res = super(users_implied, self).write(cr, uid, ids, values, context)
         if values.get('groups_id'):
             # add implied groups for all users