I found the problem. /var/log/dist-upgrade/apt.log contained the lines
Broken libk3b7-extracodecs:amd64 Depends on libavcodec58:amd64 < none | 7:4.2.2-1ubuntu1 @un uH > (>= 7:4.0) Considering libavcodec58:amd64 70 as a solution to libk3b7-extracodecs:amd64 1 MarkKeep libk3b7-extracodecs:amd64 < 17.12.3-0ubuntu3 -> 19.12.3-0ubuntu1 @ii umU Ib > FU=0 Holding Back libk3b7-extracodecs:amd64 rather than change libavcodec58:amd64 I eventually found out that libk3b7-extracodecs belongs to the DVD burning application K3B. After deinstalling K3B with apt remove k3b apt autoremove the upgrade to Ubuntu Mate 20.04 was successful. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1876298 Title: Upgrade from Ubuntu Mate 18.04 to 20.04 fails To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1876298/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
