Reinstall grub after windows breaks it

February 12 2013 : posted under linux windows grub

One of those things that happens from time to time on a dual boot system…

Windows breaks grub, usually if I’ve reinstalled windows, this can lead to a unbootable system.

Boot from a Ubuntu (or other distro) live disk or USB stick.

Figure out which your disks and partitions are.

sudo mount /dev/sdXY /mnt
# if there is a boot partition
sudo mount /dev/sdUV /mnt/boot
sudo grub-install --recheck --root-directory=/mnt /dev/sdZ

When you reboot grub should be back to normal.