diff --git a/src/browser/atom-portable.coffee b/src/browser/atom-portable.coffee
index 4037c95bb..a8cbd2d41 100644
--- a/src/browser/atom-portable.coffee
+++ b/src/browser/atom-portable.coffee
@@ -27,6 +27,6 @@ class AtomPortable
     catch error
       message = "Failed to use portable Atom home directory (#{@getPortableAtomHomePath()}).  Using the default instead (#{defaultHome}).  #{error.message}"
 
-    ipc.on 'check-portable-home-writable', (event, arg) ->
+    ipc.on 'check-portable-home-writable', (event) ->
       event.sender.send 'check-portable-home-writable-response', {writable, message}
     writable