Public bug reported: I tried to remove packages skypeforlinux and zoom that were installed, but without success.
$ sudo do-release-upgrade -d Checking for a new Ubuntu release Get:1 Upgrade tool signature [1 554 B] Get:2 Upgrade tool [1 342 kB] Fetched 1 343 kB in 0s (0 B/s) authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg' extracting 'focal.tar.gz' Reading cache Checking package manager Reading package lists... Done Building dependency tree Reading state information... Done Hit http://fr.archive.ubuntu.com/ubuntu bionic InRelease Hit http://fr.archive.ubuntu.com/ubuntu bionic-updates InRelease Hit http://fr.archive.ubuntu.com/ubuntu bionic-backports InRelease Ign http://dl.google.com/linux/chrome/deb stable InRelease Hit http://dl.google.com/linux/chrome/deb stable Release Hit https://repo.skype.com/deb stable InRelease Get:1 http://security.ubuntu.com/ubuntu bionic-security InRelease [88,7 kB] Fetched 88,7 kB in 0s (0 B/s) Reading package lists... Done Building dependency tree Reading state information... Done Checking for installed snaps Calculating snap size requirements Updating repository information Third party sources disabled Some third party entries in your sources.list were disabled. You can re-enable them after the upgrade with the 'software-properties' tool or your package manager. To continue please press [ENTER] Hit http://fr.archive.ubuntu.com/ubuntu focal InRelease Hit http://fr.archive.ubuntu.com/ubuntu focal-updates InRelease Hit http://fr.archive.ubuntu.com/ubuntu focal-backports InRelease Get:1 http://security.ubuntu.com/ubuntu focal-security InRelease [107 kB] Fetched 107 kB in 0s (0 B/s) Checking package manager Reading package lists... Done Building dependency tree Reading state information... Done Calculating the changes Calculating the changes Could not calculate the upgrade An unresolvable problem occurred while calculating the upgrade. This was likely caused by: * Unofficial software packages not provided by Ubuntu Please use the tool 'ppa-purge' from the ppa-purge package to remove software from a Launchpad PPA and try the upgrade again. If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If you want to investigate this yourself the log files in '/var/log/dist-upgrade' will contain details about the upgrade. Specifically, look at 'main.log' and 'apt.log'. Restoring original system state Aborting Reading package lists... Done Building dependency tree Reading state information... Done ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: ubuntu-release-upgrader-core 1:18.04.37 ProcVersionSignature: Ubuntu 5.3.0-51.44~18.04.2-generic 5.3.18 Uname: Linux 5.3.0-51-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.14 Architecture: amd64 CrashDB: ubuntu CurrentDesktop: ubuntu:GNOME Date: Sat May 9 23:02:52 2020 InstallationDate: Installed on 2019-08-20 (263 days ago) InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210) PackageArchitecture: all SourcePackage: ubuntu-release-upgrader UpgradeStatus: Upgraded to bionic on 2020-05-09 (0 days ago) ** Affects: ubuntu-release-upgrader (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug bionic dist-upgrade -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1877791 Title: Error during do-release-upgrade -d To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1877791/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs