diff --git a/main/inc/lib/usermanager.lib.php b/main/inc/lib/usermanager.lib.php
index 82ab00eebc..7bc4cde8f6 100755
--- a/main/inc/lib/usermanager.lib.php
+++ b/main/inc/lib/usermanager.lib.php
@@ -2751,7 +2751,8 @@ class UserManager
                 if ($session_visibility == SESSION_INVISIBLE) {
                     continue;
                 }
-
+                // This query is horribly slow when more than a few thousand
+                // users and just a few sessions to which they are subscribed
                 $id_session = $enreg['id'];
                 $personal_course_list_sql = "SELECT DISTINCT
                         course.code code,
diff --git a/main/social/groups.php b/main/social/groups.php
index 2fb3f94251..0b3c7363cb 100755
--- a/main/social/groups.php
+++ b/main/social/groups.php
@@ -10,7 +10,7 @@ $cidReset = true;
 require_once '../inc/global.inc.php';
 
 api_block_anonymous_users();
-if (api_get_setting('allow_social_tool') != 'true') {
+if (api_get_setting('allow_social_tool') != 'true' && !api_is_platform_admin()) {
     api_not_allowed();
 }