It looks like the upgrade process can't install kernel properly on btrfs. I booted with LiveUSB, chrooted to the system and finished by
dpkg --configure -a apt-get install -f -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1556446 Title: Ubuntu 14.04 crashes on upgrade to 16.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1556446/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
