diff --git a/lib/helper.php b/lib/helper.php
index ca508e1d9334dd5ad85a308babbd5977ab5b9253..31f0f1698d55c992c58ee01bbe4c61420733a241 100644
--- a/lib/helper.php
+++ b/lib/helper.php
@@ -232,7 +232,7 @@ class OC_Helper {
 	public static function humanFileSize( $bytes ) {
 		if( $bytes < 0 ) {
 			$l = OC_L10N::get('lib');
-			return $l->t("couldn't be determined");
+			return "?";
 		}
 		if( $bytes < 1024 ) {
 			return "$bytes B";