IISExpress Broken after Windows 10 Threshold 2 Upgrade


  • I've been running a local web site and API in IISExpress on Windows 10 / VS2015 with various bindings to expose on my local network for testing. All has been working splendidly.

    Using the usual netsh commands to open ports etc. Everything has been working fine.


    netsh http add urlacl url=http://<your-ip-address>:54275/ user=everyone
    netsh advfirewall firewall add rule name=”IISExpressWeb” dir=in protocol=tcp localport=54275 profile=private remoteip=localsubnet action=allow

    Yesterday I did the Threashold 2 upgrade on this box, boom. Broken.

    I've checked all the settings I can think of. My applicationHost.config is fine, the firewall rules are fine. As far as I can tell, all the custom settings that I had made in order to get this working are still valid and in place yet I now see this error.


    Checking the event log I see one IISExpress error:

    "The worker process for app pool 'Clr4IntegratedAppPool', PID='8196', failed to initialize the http.sys communication when asked to start processing http requests and therefore will be considered ill by W3SVC and terminated. The data field contains the error number."

    Detail view shows:

    Binary data: In Words 0000: 800704D0

    I'm completely at a loss as to what the real problem is now. Has anyone fixed this situation?


    Everything I can find about this details this solution, which I've checked current settings / tried but this hasn't fixed the issue.


    Thursday, December 3, 2015 12:41 PM


  • Hi findjammer,

    Please create a new web site and API with VS2015 and run it to make sure this problem is related to all web site or just this specific one.

    If just for this specific project, please create a new one and then move the files and all settings one by one to make sure which file or setting causes this problem.

    If for all website, please try repair the IIS Express from Control Panel -> Right-click IIS Express -> Repair. And also repair Visual Studio with the same step.

    According to the event log, this may be caused by the error version of http.sys file, which may be modified when upgrading. The http.sys version should be 10586, not 10240.

    In addition, please try to remove this update from Control Panel -> Installed Updates to confirm this problem is caused by this update.

    Best Regards,

    Friday, December 4, 2015 8:04 AM