Vista SP1 won't install on dual-boot systems: Microsoft
Are you currently running Windows and Linux in a dual-boot setup? You're going to have major headaches with Vista SP1, Microsoft has admitted.
If youre dualbooting Windows Vista Enterprise or Ultimate alongside a Linux distro, and have installed the Linux bootloader into the MBR, then youre guaranteed to run into problems when installing Vista Service Pack 1, Microsoft has admitted.
The service pack has a couple of prerequisite updates and one of them, KB935509, contains an update to the Windows Vista bootloader. However, this bootloader is often replaced by open source bootloaders like Grub when installing Linux onto a system.
Microsoft has excused itself by saying Vista SP1 contains an update to the BitLocker feature, and replacing the bootloader is a necessary prerequisite just in case the system being serviced contains a drive encrypted with BitLocker or worse, an encrypted boot partition.
To read the whole article, see here. This story came out in March, but I couldn't find any mention of it in CF