OS uninstallable

[Colin Law]

On Fri, 24 Mar 2023 at 21:31, Bret Busby <bret at busby.net> wrote:
>
> Hello.
>
> I have just spent about five hours unsuccessfully trying to install each
> of Linux Mint Mate 21.1, Linux Mint Mate 21, and UbuntuMate 22.04 .
>
> It goes through the installation process, then terminates with the
> unintelligible error
>
> "Unable to install GRUB (as superuser)
> Executing 'grubinstall failed.
> This is a fatal error"

Are you sure you are telling it to install on the correct drive?
Remember the allocations may be different to your usual setup when
booting off a USB stick.

Colin