diff --git a/src/web/app/desktop/script.js b/src/web/app/desktop/script.js
index 6beba44ff..f9f0896dd 100644
--- a/src/web/app/desktop/script.js
+++ b/src/web/app/desktop/script.js
@@ -41,6 +41,8 @@ init(async (me, stream) => {
 });
 
 function registerNotifications(stream) {
+	if (stream == null) return;
+
 	stream.on('drive_file_created', file => {
 		const n = new Notification('ファイルがアップロードされました', {
 			body: file.name,