I am trying to setup Ubuntu on an external USB hard drive to see if I can reliably move it between computers. This has been far harder than I thought it would be.
I got the external HDD to boot and run quite well on my laptop (which is 6 months old, core i3, 4gb ram). I can switch between my USB drive's Ubuntu 16.04.2 and my local drive (which has both Ubuntu 16.04.2 and Windows 10). So far, so good.
When I try to boot that same drive on my desktop computer (7 years old, core i7, 12GB ram), it will not boot. When I set the external HDD to be my boot drive (in the bios), I get the following error:
error: file '/boot/grub/i386-pc/normal.mod' not found.
Entering rescue mode...
When I set my local hdd to be my boot drive and then choose the external hdd from the grub menu, I get the following error:
error: file '/boot/bmlinuz-4.8.0-56-generic.efi.signed' not found.
error: you need to load the kernel first.
Press any key to continue...
Then I get bounced back to the local hdd's grub menu.
My question is, why can this drive boot fine from a newish laptop but not from a more powerful, but older, desktop computer?
I did install Ubuntu on the external drive from the laptop but I have tried many variations including using 17.04 and installing from the desktop. Regardless of what I try (including many of the recommendations from this site) I am unable to get my external drive to boot from my older desktop computer.
Any ideas are welcome.