I have a triple boot windows 7, ubuntu 10.10, ubuntu 11.10 and i want to delete the partitiion containing 11.10 but that's where my grub is located I believe. Because it updated to grub 1.99 when I downloaded installed 11.10. How can I change this so that even after the partition is deleted I can use grub.

3 Answers 3


You don't have to boot from exact Ubuntu version, you can run grub-install with --root-directory option (if your required partition is mounted to /mnt):

grub-install --root-directory=/mnt /dev/sda

It's a good idea to have a separate /boot partition.


Try this -

Boot from Ubuntu 10.10 ( which u don't want to delete ), Open terminal and type command sudo grub-install /dev/sda . And then sudo reboot . If now grub of Ubuntu 10.10 is there, then you can safely delete partitions of 11.10 and remove the entry of 11.10 from /boot/grub/grub.cfg


Boot from a live cd like on of your ubuntu install cds and open a Terminal. Now mount one of your ubuntu partitions. Assuming /dev/sda7 is your ubuntu 11.10 partition you can accomplish this by issuing the following command as root user:

sudo -s
mount /dev/sda7 /mnt

Now you can use chroot to change in the mounted operating system:

chroot /mnt

Now it should be easy to use grub-install:

grub-install /dev/sda

Now change to /etc/grub.d/ where you should find a script called 30-os-prober. This script will scan the hard disks for other operating systems and add them to the boot menu. Therefor as root you should execute this script:

sudo /etc/grub.d/30-os-prober

And as final step update your grub.


Also i found this helpful site.

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