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I currently have 3 partitions: Windows, Ubuntu, and swap.

I want to move my windows partition by about 20GB. When I try to do this in GParted, it tells me that this will mess up GRUB, and that there is a page that can resolve these issues.

However, this page does not actually mention my issue. I am not moving my boot partition (Ubuntu).

How can I force GRUB to look for operating systems that are on the drive? I know that this is possible, because when Ubuntu was installed it found Windows without any issues.

Additionally, if I create a copy of a partition, how can I add that to GRUB (I assume it will be the same command as above, but if not, what would it be)?

Note: OS prober is mentioned here but it doest not list how to use it, or where to find it.

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up vote 5 down vote accepted

You can always use sudo update-grub command to automatically probe for Operating systems in the Drive. Yes, It will do it automagically.


  • Open a terminal, by pressing Super key, which is also called as Windows key, type terminal, hit Enter

  • Type sudo update-grub and wait to see what it says.

  • If you see messages like "Microsoft Windows XP is found in /dev/sda1" or like it is done.

An example run returned this output in my system. Your output may vary.

student@student-ThinkCentre-A70:~$ sudo update-grub
[sudo] password for student: 
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-3.2.0-23-generic-pae
Found initrd image: /boot/initrd.img-3.2.0-23-generic-pae
Found linux image: /boot/vmlinuz-2.6.35-22-generic
Found initrd image: /boot/initrd.img-2.6.35-22-generic
Found memtest86+ image: /boot/memtest86+.bin
Found Microsoft Windows XP Professional on /dev/sda1

Hope this will help.

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