diff --git a/system/src/Grav/Common/User/User.php b/system/src/Grav/Common/User/User.php
index 9caad3741..4ba6a20c4 100644
--- a/system/src/Grav/Common/User/User.php
+++ b/system/src/Grav/Common/User/User.php
@@ -32,6 +32,9 @@ class User extends Data
     {
         $locator = self::getGrav()['locator'];
 
+        // force lowercase of username
+        $username = strtolower($username);
+
         $blueprints = new Blueprints('blueprints://');
         $blueprint = $blueprints->get('user/account');
         $file_path = $locator->findResource('account://' . $username . YAML_EXT);