All right I had a quick peak in the log files. svcpack.log was the most interesting one. Near the bottom, just before the errormsg I found this: 105.204: UnRegisterSpuninstForRecovery, failed to delete SpRecoverCmdLine value, error 0x2 105.204: DoInstallation: Failed to unregistering spuninst.exe for recovery. 105.219: An internal error occurred. 109.641: Message displayed to the user: An internal error occurred. 109.641: User Input: OK 109.641: Service Pack 2 installation did not complete. so spuninst.exe failed to unregister... I have disabled restore points, but this shouldn't affect the SP2 install as I also have done this on my laptop. Can it be because I have an unattended windows install laying on my harddrive? (not the actual install, but all the files)