diff --git a/lib/classes/user.php b/lib/classes/user.php
index a125173e170..06dbd91fa1d 100644
--- a/lib/classes/user.php
+++ b/lib/classes/user.php
@@ -788,6 +788,7 @@ class core_user {
      */
     public static function reset_caches() {
         self::$propertiescache = null;
+        self::$preferencescache = null;
     }
 
     /**