diff --git a/modoboa/admin/__init__.py b/modoboa/admin/__init__.py
index eead1b284..1f904eb1d 100644
--- a/modoboa/admin/__init__.py
+++ b/modoboa/admin/__init__.py
@@ -240,7 +240,13 @@ class GeneralParametersForm(parameters.AdminParametersForm):
         values = self.get_current_values()
         if not ldap_available or values["authentication_type"] != "ldap":
             return
-        ldap_uri = 'ldap://' if values["ldap_secured"] == "yes" else "ldaps://"
+        if not hasattr(settings, "AUTH_LDAP_USER_ATTR_MAP"):
+            setattr(settings, "AUTH_LDAP_USER_ATTR_MAP", {
+                "first_name": "givenName",
+                "email": "mail",
+                "last_name": "sn"
+            })
+        ldap_uri = 'ldaps://' if values["ldap_secured"] == "yes" else "ldap://"
         ldap_uri += "%s:%s" % (values["ldap_server_address"], values["ldap_server_port"])
         setattr(settings, "AUTH_LDAP_SERVER_URI", ldap_uri)
         if values["ldap_auth_method"] == "searchbind":
@@ -254,6 +260,14 @@ class GeneralParametersForm(parameters.AdminParametersForm):
         else:
             setattr(settings, "AUTH_LDAP_USER_DN_TEMPLATE", values["ldap_user_dn_template"])
 
+        if values["ldap_is_active_directory"] == "yes":
+            if not hasattr(settings, "AUTH_LDAP_GLOBAL_OPTIONS"):
+                setattr(settings, "AUTH_LDAP_GLOBAL_OPTIONS", {
+                    ldap.OPT_REFERRALS: False
+                })
+            else:
+                settings.AUTH_LDAP_GLOBAL_OPTIONS[ldap.OPT_REFERRALS] = False
+
 parameters.register(GeneralParametersForm, ugettext_lazy("General"))
 
 
diff --git a/modoboa/admin/models.py b/modoboa/admin/models.py
index 4659e3a46..6deebe21c 100644
--- a/modoboa/admin/models.py
+++ b/modoboa/admin/models.py
@@ -555,6 +555,7 @@ class Domain(DatesAware):
             events.raiseEvent("DomainAliasDeleted", self.domainalias_set.all())
             ungrant_access_to_objects(self.domainalias_set.all())
         if self.mailbox_set.count():
+            Quota.objects.filter(username__contains='@%s' % self.name).delete()
             events.raiseEvent("DeleteMailbox", self.mailbox_set.all())
             ungrant_access_to_objects(self.mailbox_set.all())
             hm = parameters.get_admin("HANDLE_MAILBOXES", raise_error=False) 
@@ -724,8 +725,10 @@ class Mailbox(DatesAware):
             self.quota = value
 
     def get_cur_quota(self):
+        if not self.quota:
+            return 0
         q = Quota.objects.get(username=self.full_address)
-        return q.bytes / (self.quota * 1048576) * 100
+        return int(q.bytes / float(self.quota * 1048576) * 100)
 
     def save_from_user(self, localpart, domain, user, quota=None, owner=None):
         """Simple save method called for automatic creations
@@ -743,8 +746,19 @@ class Mailbox(DatesAware):
         Quota.objects.create(username=self.full_address)
 
     def delete(self, keepdir=False):
-        q = Quota.objects.get(username=self.full_address)
-        q.delete()
+        """Custom delete method
+
+        We try to delete the associated quota in the same time (it may
+        has already been removed if we're deleting a domain).
+
+        :param bool keepdir: delete the mailbox home dir on the filesystem or not
+        """
+        try:
+            q = Quota.objects.get(username=self.full_address)
+        except Quota.DoesNotExist:
+            pass
+        else:
+            q.delete()
         super(Mailbox, self).delete()
         if not keepdir:
             self.delete_dir()
@@ -964,24 +978,18 @@ class Extension(models.Model):
 
         events.raiseEvent("ExtDisabled", self)
 
-def populate_callback(sender, user=None, **kwargs):
-    """Populate signal callback
+def populate_callback(user):
+    """Populate callback
 
     If the LDAP authentication backend is in use, this callback will
     be called each time a new user authenticates succesfuly to
     Modoboa. This function is in charge of creating the mailbox
     associated to the provided ``User`` object.
 
-    :param sender: ??
     :param user: a ``User`` instance
     """
     from modoboa.lib.permissions import grant_access_to_object
 
-    if parameters.get_admin("AUTHENTICATION_TYPE") != "ldap":
-        return
-    if user is None:
-        return
-
     sadmins = User.objects.filter(is_superuser=True)
 
     user.groups.add(Group.objects.get(name="SimpleUsers"))
@@ -1013,11 +1021,3 @@ def populate_callback(sender, user=None, **kwargs):
         grant_access_to_object(sadmins[0], mb, True)
         for su in sadmins[1:]:
             grant_access_to_object(su, domain)
-
-
-try:
-    from django_auth_ldap.backend import populate_user
-except ImportError, inst:
-    pass
-else:
-    populate_user.connect(populate_callback, dispatch_uid="myuid")
diff --git a/modoboa/admin/static/admin/js/admin.js b/modoboa/admin/static/admin/js/admin.js
index 3db113d36..72dfb7383 100644
--- a/modoboa/admin/static/admin/js/admin.js
+++ b/modoboa/admin/static/admin/js/admin.js
@@ -122,13 +122,13 @@ Domains.prototype = {
         var deloptions = (data.handle_mailboxes)
             ? {keepdir: gettext("Do not delete domain directory")}
             : {};
-        var warnmsg = (data.auto_account_removal)
+        var warnmsg = (data.auto_account_removal && data.auto_account_removal == "yes")
             ? gettext("This operation will remove ALL data associated to this domain.")
             : gettext("This operation will remove all data associated to this domain, excepting accounts.");
 
         $("a[name=deldomain]").confirm({
             question: gettext("Delete this domain?"),
-            warning: gettext("This operation will remove ALL data associated to this domain."),
+            warning: warnmsg,
             checkboxes: deloptions,
             success_cb: $.proxy(this.reload_listing, this)
         });
diff --git a/modoboa/admin/views.py b/modoboa/admin/views.py
index 99a808b88..407088eac 100644
--- a/modoboa/admin/views.py
+++ b/modoboa/admin/views.py
@@ -505,6 +505,7 @@ def saveparameters(request):
         form = formdef["form"]
         if form.is_valid():
             form.save()
+            form.to_django_settings()
             continue
         return ajax_simple_response({"status": "ko", "prefix": form.app, "errors": form.errors})
     return ajax_simple_response(dict(status="ok", respmsg=_("Parameters saved")))
diff --git a/modoboa/lib/authbackends.py b/modoboa/lib/authbackends.py
index b27a05ccd..db5ec34e1 100644
--- a/modoboa/lib/authbackends.py
+++ b/modoboa/lib/authbackends.py
@@ -1,5 +1,6 @@
 from django.contrib.auth.backends import ModelBackend
 from modoboa.admin.models import User
+from modoboa.lib import parameters
 
 class SimpleBackend(ModelBackend):
 
@@ -20,6 +21,8 @@ class SimpleBackend(ModelBackend):
 
 try:
     from django_auth_ldap.backend import LDAPBackend as orig_LDAPBackend, _LDAPUser
+    from modoboa.admin.models import populate_callback
+
 
     class LDAPBackend(orig_LDAPBackend):
 
@@ -29,10 +32,13 @@ try:
             username is the Django-friendly username of the user. ldap_user.dn is
             the user's DN and ldap_user.attrs contains all of their LDAP attributes.
             """
-            return User.objects.get_or_create(
+            user, created = User.objects.get_or_create(
                 username__iexact=username, 
                 defaults={'username': username.lower()}
-                )
+            )
+            if created:
+                populate_callback(user)
+            return user, created
 
         def get_user(self, user_id):
             user = None
@@ -43,5 +49,11 @@ try:
                 pass
             return user
 
+        def authenticate(self, username, password):
+            auth_type = parameters.get_admin("AUTHENTICATION_TYPE", app="admin")
+            if auth_type == "ldap":
+                return super(LDAPBackend, self).authenticate(username, password)
+            return None
+
 except ImportError:
     pass