WSUS IIS APPLICATION POOL shuts down

Select the Application Pool Name and then click ‘Advanced Settings’.
Do some changes:

Private Memory Limit (KB): 1843200 to 4194304

Queue Length: 1000 to 25000

Limit Interval (minutes): 5 to 15

‘Service Unavailable’ Response: HttpLevel to TcpLevel

Then stop the IIS (IIS-Manager or ‘net stop w3srv’), edit the web.config ( C:\Program Files\Update Services\WebServices\ClientWebService\web.config ) for WSUS:
Replace <httpRuntime maxRequestLength=”4096″ /> with <httpRuntime maxRequestLength=”204800″ executionTimeout=”7200″/>

If you cant save the file, move it to another place, modify it and move it back.

If you are a daredevil set Private Memory Limit to 0 (unlimited.)