Upgrade to 20.04 crashes even after disabling all 3rd party software sources

[Jerome Jung]

I tried to upgrade ubuntu from 18 to 20.04. First it crashed complaining that I should purge 3rd party ppa's. After I disabled them in the software & update under the other software section it still crashes at the same point with an reduced error message as follows:

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 1:18.04.44
ProcVersionSignature: Ubuntu 5.4.0-72.80~18.04.1-generic 5.4.101
Uname: Linux 5.4.0-72-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.23
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Wed May 5 11:57:29 2021
InstallationDate: Installed on 2019-06-19 (685 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2021-05-05 (0 days ago)
VarLogDistupgradeTermlog:

[Chris Guiver (guiverc)]

Thank you for taking the time to report this issue and helping to make Ubuntu better.

The error message you likely saw says

"* 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."

The ppa-purge tool doesn't just disable sources, but removes the packages that were installed from those sources. It's the installed packages that create the problem in upgrade.

I looked and do see evidence of 3rd party (PPA) packages present, so I suggest support is in order.

I've marked this incomplete, as you haven't followed the PPA purge instructions and removed all 3rd party software before upgrade to proceed. If you believe I'm in error, or have missed something, please leave a comment explaining why, and you can return the status to "New".

[Launchpad Janitor (janitor)]

[Expired for ubuntu-release-upgrader (Ubuntu) because there has been no activity for 60 days.]