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Service Unavailable after Windows 10 Update

After updating to Windows 10 Fall Creators update, we encountered the Service Unavailable 503 message on our IIS websites.

The error looks like this:

The worker process for application pool 'APP_POOL_NAME' encountered an error
'Cannot read configuration file ' trying to read configuration data from file '\?\',
line number '0'. The data field contains the error code.

A solution that worked, is this:

  1. Stop the IIS - run iisreset /stop command in your command prompt.
  2. Remove everything in the c:/inetpub/temp/apppools folder. If you can't, look below for a few PowerShell commands you need to run.
  3. Start the IIS - run iisrest /start command in your command prompt.
  4. Make sure all your IIS app pools are running.
If you can't remove the files in the apppools folder, use Windows PowerShell to stop two services:
  1. Stop-Service -Force WAS.
  2. Stop-Service W3SVC.
  3. Remove apppols folder files.
  4. Run Start-Service W3SVC.


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