I have a fault regarding IIS 7.5 on Win Server 2008 R2, whenever I try to change any site bindings or start an application pool I get the error below: Filename: \\?\C:\Windows\system32\inetsrv\config\applicationHost.config Error: Cannot write configuration file the application pools run as network service. None of the sites that are running have been affected however their configuration cannot be changed UPDATED 05/10/2012 A reboot fixed this issue, however I am curious to know what caused it in the first place.