After a lot of investigation this turned out to be an issue with libsane. After reinstalling it I managed to upgrade to 20.04.
It would be however very useful to get some debug information which package is blocking the update. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1907929 Title: Upgrade from 18.04 to 20.04 fails with "pkgProblemResolver::Resolve generated breaks, this may be caused by held packages" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1907929/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
