I was able to recreate this bug by using the apt-clone file in it, after restoring the clone file the upgrade failed to calculate. When I removed the fpc package the upgrade was calculatable so it seems to be an issue with the fpc packages.
** Summary changed: - upgrade 16.04 to 18.04 + upgrade from 16.04 to 18.04 uncalculatable due to fpc packages -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1786486 Title: upgrade from 16.04 to 18.04 uncalculatable due to fpc packages To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1786486/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
