diff --git a/atom/browser/lib/chrome-extension.coffee b/atom/browser/lib/chrome-extension.coffee
index 3a62da57b43b..6ca1bc1651dd 100644
--- a/atom/browser/lib/chrome-extension.coffee
+++ b/atom/browser/lib/chrome-extension.coffee
@@ -8,7 +8,7 @@ hostPathMap = {}
 hostPathMapNextKey = 0
 
 getHostForPath = (path) ->
-  key = "extension-#{hostPathMapNextKey}"
+  key = "extension-#{++hostPathMapNextKey}"
   hostPathMap[key] = path
   key
 
@@ -23,6 +23,8 @@ app.once 'ready', ->
     parsed = url.parse request.url
     return unless parsed.hostname and parsed.path?
 
+    return unless /extension-\d+/.test parsed.hostname
+
     directory = getPathForHost parsed.hostname
     return new protocol.RequestFileJob(path.join(directory, parsed.path))