title: IIS7 Itegrated Pipeline Mode: Context.User is intermittently null for Windows Auth
body: <p>Our code relies on checking the Context.User.Identity value in the Global.asax Application_AuthenticateRequest(...) method to retrieve some information about the logged in user.  This works fine in classic mode but when I flip IIS to use the Integrated Pipeline "Context.User" comes back as null, but only intermittently.  Any ideas why?</p>
  
  <p>I have &lt; authentication mode="Windows"> and only Windows Auth enabled in the Virtual Directory.</p>