I seem to be having a nightmare trying to install Microsoft Service Pack 1 for Windows 2008 R2 x64 on top of SBS 2011. I have tried the ISO and the EXE download and windows update for the service pack and all fail. The error message i get is:
ERROR_FILE_NOT_FOUND (0x80070002) Installation was not sucessfull.
I am able to run the System Update Readiness tool fine and it completes 100% no errors.
sfc /scannowreturns no errors.
SBS 2011 is patched and i do not really wish to uninstall all the Windows Updates to then try SP1 install again.