You are trying to update a Windows to Go installation to another build. Windows Update checks if the installation is a Windows to Go installation. You must use registry editor to fake the installation to not be a Windows to Go installation.
There's a very easy solution to bypass this! Just open the registry go to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control Now look for: PortableOperatingSystem And change the REG_WORD value from 1 to 0 And try again, as soon as it starts installing, change it back to 1 I have done this with previous build and it works everytime! Good Luck!