diff --git a/modoboa/extensions/admin/forms/domain.py b/modoboa/extensions/admin/forms/domain.py
index f19742377..6cefdb9f7 100644
--- a/modoboa/extensions/admin/forms/domain.py
+++ b/modoboa/extensions/admin/forms/domain.py
@@ -115,8 +115,6 @@ class DomainFormGeneral(forms.ModelForm, DynamicForm):
                 '@%s' % self.oldname, '@%s' % domain.name)
             newq = Quota.objects.create(
                 username=username, bytes=q.bytes, messages=q.messages)
-            q.mailbox.quota_value = newq
-            q.mailbox.save()
             q.delete()
 
     def save(self, user, commit=True, domalias_post_create=False):