Comment 13 for bug 1766890

FWIW, this error (my bug was marked a duplicate) completely broke my Xenial - Bionic upgrade, leaving me with a nearly unbeatable system. I had to boot into Rescue Mode and do a lot of ctrl-C ing to get around this, and once I thought it had finally installed all the bionic packages, I rebooted into the OS proper, and STILL found it hadn't actually upgraded so I had to run 'apt-get -f install' again to finish the other 2400+ package updates.

I spent most of my morning just trying to get back to a bootable system that was only half-way upgraded (lsb-release told me I was in 18.04, name -a said I was still on 4.13 from 16.04.4, and apt said I still had 2400+ packages to update).

If I was not an experienced user who knew roughly how to manually kick this stuff to get around broken package updates, I'd have been considerably more upset than I already am.