diff --git a/sw.js b/sw.js
index 96a1186..49f16a9 100644
--- a/sw.js
+++ b/sw.js
@@ -11,7 +11,7 @@ self.addEventListener('activate', e => {
     e.waitUntil(
         caches.keys().then(keys =>
             Promise.all(keys.filter(k => k !== CACHE).map(k => caches.delete(k)))
-        )
+        ).catch(err => console.warn('[SW] activate error', err))
     );
     self.clients.claim();
 });