diff --git a/install-usercss/install-usercss.js b/install-usercss/install-usercss.js
index 2361112b..afbd6419 100644
--- a/install-usercss/install-usercss.js
+++ b/install-usercss/install-usercss.js
@@ -335,7 +335,7 @@
 
     // live reload
     const setLiveReload = $('.live-reload input[type=checkbox]');
-    if (updateUrl.protocol !== 'file:') {
+    if (!installationUrl || !installationUrl.startsWith('file:')) {
       setLiveReload.parentNode.remove();
     } else {
       setLiveReload.addEventListener('change', () => {