diff --git a/src/app.js b/src/app.js
index acaaf45358..c3b27b5bfc 100644
--- a/src/app.js
+++ b/src/app.js
@@ -378,6 +378,8 @@ function run () {
         // FIXME: at some point we should invalidate the browser cache
         filesProviders['browser'].addReadOnly(url, content)
         cb(null, content)
+      } else {
+        cb(error)
       }
     })
   })