IIS 10 - Cannot read \\?\<EMPTY> configuration file

Everything worked correctly on my IIS, but I installed Windows Fall Creators Update and everything stopped working.

I get an 503 - Service Unavailable error on every app and page inside my AppPool I visit. I've checked the Windows event viewer and it says the following:

I've searched among the web and none of the solutions work (permissions, credentials...). I've even uninstalled completely IIS (with WAS included) and reinstalled it to reset to its factory settings. All my applications now are gone (as expected), but I still get the same error.

My system is a Windows 10 Pro (version 1709) Lenovo laptop. No updates are available on Windows Update.

More information of the error on Event Viewer:

What's wrong with my IIS configuration and how can I make it to work again?

Solution 1:

The issue is related to the temporary symbolic links created for the application pools by IIS/WAS being messed up during the Windows Update process for installing Fall Creators Update.

The steps to solve the problem are (at an administrator powershell):

Stop-Service -Force W3SVC
Stop-Service -Force WAS
Foreach($item in Get-ChildItem C:\inetpub\temp\appPools){
  if([IO.File]::Exists($item.FullName)){
    Remove-Item $item -Force
  } else {
    [IO.Directory]::Delete($folder.FullName,$true);
  }
}
Start-Service W3SVC 
Start-Service WAS

Deleting everything (files, folders and shortcuts) under "c:\inetpub\temp\apppools" will clear the temp files and the incorrect symbolic links, and starting IIS/WAS again should create them back and fix the issue.

Edit Microsoft have documented the issue in the following KB: https://support.microsoft.com/en-us/help/4050891/error-http-503-and-was-event-5189-from-web-applications-on-windows-10