Background:
I have been running Ubuntu MATE for a little over a year. I originally installed 16.04 LTS and then this year upgraded to 18.04 LTS, without any problems. Everything was great.
Issue:
I decided to upgrade the HDD in my Lenovo V570 to an SSD. Every time I boot my computer, I go to GRUB prompt. Even when I manually chose to boot from my SSD. I found this post - except in my case, I did not see the grub rescue prompt, but grub prompt instead.
So now, I always have to run the following commands on GRUB prompt, every single time I boot my computer, but at least I am making some progress! I followed this post explaining why and how to delete the MBR.)
grub> root=(hd0,gpt2)
grub> configfile /boot/grub/grub.cf
After booting into my system, I did this, but the issue persists:
$ sudo grub-install /dev/sda
Installing for x86_64-efi platform.
Installation finished. No error reported.
$ sudo update-grub
Generating grub configuration file ...
Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported.
Found linux image: /boot/vmlinuz-4.15.0-23-generic
Found initrd image: /boot/initrd.img-4.15.0-23-generic
Found linux image: /boot/vmlinuz-4.15.0-20-generic
Found initrd image: /boot/initrd.img-4.15.0-20-generic
done