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.