Problem: When trying to upgrade the SharePoint to a higher service pack you encounter this error in the log
[OWSTIMER] [SPUpgradeSession] [ERROR] [11/3/2014 2:56:24 PM]: Upgrade Timer job is exiting due to exception: Microsoft.SharePoint.Upgrade.SPUpgradeException: Action 18.104.22.168 of Microsoft.SharePoint.Upgrade.SPIisWebSiteWssSequence failed. —> System.Runtime.InteropServices.COMException (0x80070003): The system cannot find the path specified.
One probably cause is the someone manually changed the Application Pool account from IIS Manager instead of using SharePoint Central Admin.
- Go to the Central Administration
- In the CA go to Application Management->Manage services on server
- Stop Microsoft SharePoint Foundation Web Application #This removes the SharePoint iis configuration
- Start Microsoft SharePoint Foundation Web Application #This recreates the SharePoint iis websites.