diff --git a/rhodecode/apps/admin/views/users.py b/rhodecode/apps/admin/views/users.py
--- a/rhodecode/apps/admin/views/users.py
+++ b/rhodecode/apps/admin/views/users.py
@@ -68,7 +68,6 @@ class AdminUsersView(BaseAppView):
         order_by = {
             'first_name': 'name',
             'last_name': 'lastname',
-            'last_activity': ''
         }.get(order_by) or order_by
 
         search_q = request.GET.get('search[value]')
diff --git a/rhodecode/templates/admin/users/users.mako b/rhodecode/templates/admin/users/users.mako
--- a/rhodecode/templates/admin/users/users.mako
+++ b/rhodecode/templates/admin/users/users.mako
@@ -68,7 +68,7 @@
                   "sort": "last_name"}, title: "${_('Last Name')}", className: "td-user" },
          { data: {"_": "last_activity",
                   "sort": "last_activity",
-                  "type": Number}, title: "${_('Last activity')}", className: "td-time", orderable: false },
+                  "type": Number}, title: "${_('Last activity')}", className: "td-time" },
          { data: {"_": "active",
                   "sort": "active"}, title: "${_('Active')}", className: "td-active" },
          { data: {"_": "admin",