[Bug 1924951] Re: Cannot upgrade from 18.04 to 20.04 "An unresolvable problem occured while calculating the upgrade."

[Brian Murray]

The error that you encountered was with calculating the upgrade, which
only changes your /etc/apt/sources.list file from your old release to
the new one and then calculates the upgrade. To test the fix it would be
enough to just run the upgrade process to the point where it asks you if
you want to upgrade and then quit the process. That being said I've
enough positive feedback so far to feel confident that the change works
so do whatever you feel comfortable with.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubuntu-release-upgrader in
Ubuntu.
https://bugs.launchpad.net/bugs/1924951

Title:
  Cannot upgrade from 18.04 to 20.04 "An unresolvable problem occured
  while calculating the upgrade."

Status in ubuntu-release-upgrader package in Ubuntu:
  Incomplete

Bug description:
  Description:	Ubuntu 18.04.5 LTS
  Release:	18.04

  I clicked the button to upgrade the system in the dialogue box that
  popped up telling me that there is a new version of the OS I can
  upgrade to.

  After the Distribution upgrade was running for a short while, it
  showed the following error message:

  Could not calculate the upgrade

  An unresolvable problem occurred while calculating the upgrade.

   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'.

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: ubuntu-release-upgrader-core 1:18.04.42
  ProcVersionSignature: Ubuntu 5.4.0-62.70~18.04.1-generic 5.4.78
  Uname: Linux 5.4.0-62-generic x86_64
  NonfreeKernelModules: nvidia_modeset nvidia
  ApportVersion: 2.20.9-0ubuntu7.21
  Architecture: amd64
  CrashDB: ubuntu
  CurrentDesktop: ubuntu:GNOME
  Date: Mon Apr 19 10:28:34 2021
  InstallationDate: Installed on 2019-09-17 (579 days ago)
  InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to bionic on 2021-04-19 (0 days ago)
  VarLogDistupgradeTermlog:

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1924951/+subscriptions