Grub: file not found

[Ralf Mardorf]

Most if not all good distros don't force to install a bootloader.
Some distros, such as *buntus nowadays might force to do it, but it
doesn't matter, after installing it, you simply can chroot to the
original bootloader Linux install and reinstall the bootloader or simply
stay with the new installed bootloader for the new installed *buntu,
even this doesn't cause issues.

Your claim simply is wrong!

My point is, that I've got several Linux distros, FreeBSD and for
hardware testing even XP installed and I installing and remove operating
systems for more than 10 years now.

However, my reply was the only reply providing help, since I didn't
mention nonsense, but ask to provide more information.