Your sources.list file in /etc/apt/ is missing the release pocket for main and restricted so the release upgrade failed. You'll want a line like the following.
deb http://archive.ubuntu.com/ubuntu/ xenial main restricted It actually exists in your /etc/apt/sources.list file but is commented out. ** Changed in: ubuntu-release-upgrader (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1819512 Title: crash during dist upgrade ... dunno why To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1819512/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
