I recently performed a clean install of Windows 11 on a 500GB SSD which went through fine.
I then installed Ubuntu alongside Win 11, which again went through fine.
Finally I installed Rocky Linux in a 3 OS boot set up, again with no problems, using defaults for all of the OS installs.
Now when I boot into GRUB at startup, I can access Win 11 and Rocky, but not Ubuntu. There are lots of GRUB boot entries for Ubuntu, but all produce errors and do not load Ubuntu.
Any ideas anyone?
First guess is that Rocky changed the UUID of the swap partition. That often happens with multiboots. Try mounting the Ubuntu partition from Rocky, and change its /etc/fstab swap entry to /dev/sdX (with X being whatever partition is being used for swap) instead of the UUID, and see if that does it. There are plenty of other ways, but that’s probably the quickest to test if that’s the problem.
Thanks for getting back to me Scott.
Before testing your solution, I decided to experiment with my UEFI boot options. I have 3 entries: Windows, Ubuntu, and Rocky Linux.
If I change first boot to either of these it will load the corresponding OS.
Therefore I am reluctant to mess about with the bootloaders since this should solve my problem. I should be able to press F12 at boot to select the desired OS.