diff --git a/admin/admin_ug_auth.php b/admin/admin_ug_auth.php
index 2688e010..9dd53a28 100644
--- a/admin/admin_ug_auth.php
+++ b/admin/admin_ug_auth.php
@@ -205,7 +205,7 @@ if ($mode == 'user' && (!empty($_POST['username']) || $user_id))
 	{
 		$this_userdata = get_userdata($_POST['username'], true);
 	}
-	elseif (!empty($user_id))
+	elseif (isset($user_id))
 	{
 		$this_userdata = get_userdata($user_id);
 	}