I ran into a weird problem with Ubuntu 18.04 on one of my computers recently. I was performing a regular software update via the Software Updater GUI when the install got stuck at Installing for x86_64-efi partition. I left the computer for a couple of hours but the install never moved beyond this point, so I had to find the updater process and kill it. I had a feeling that things weren’t going to behave nicely after a reboot since I had interrupted an update in the middle of a GRUB install.
