The second service pack 2 for Windows Vista and Windows Server 2008 will fail to install on computers that have cloned disks or partitions via what Microsoft referred to as third-party disk management tools. When you install Vista SP2, the Vista SP2 installer must update the system boot files. If third-party disk management tools are used to "clone" disks or partitions, the SP2 installer will be unable to uniquely identify the correct system boot files.” “To work around this issue, turn off the computer and physically unplug all drives that are not required for starting Windows. Power up the computer and restart the service pack installation. If the workaround is not successful, the alternative is to perform a clean-install,” explained Microsoft via KB971204.