You seem to not have the kubuntu-desktop metapkg installed. Please manually install that package and try the upgrade again, thanks in advance!
2021-03-04 18:44:38,965 DEBUG none of the '['ubuntu-desktop', 'kubuntu-desktop', 'xubuntu-core', 'xubuntu-desktop', 'ubuntustudio-desktop', 'mythbuntu-desktop', 'kubuntu-netbook', 'lubuntu-desktop', 'ubuntu-gnome-desktop', 'ubuntu-mate-core', 'ubuntu-mate-desktop', 'ubuntukylin-desktop', 'ubuntu-budgie-desktop']' meta-pkgs installed 2021-03-04 18:44:38,965 DEBUG guessing 'kubuntu-desktop' as missing meta-pkg 2021-03-04 18:44:39,199 ERROR failed to mark 'kubuntu-desktop' for install (E:Unable to correct problems, you have held broken packages.) 2021-03-04 18:44:39,698 ERROR Dist-upgrade failed: 'Broken packages after upgrade: kubuntu-desktop' ** Changed in: ubuntu-release-upgrader (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1917790 Title: An unresolvable problem occurred while calculating the upgrade. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1917790/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs