Unable to upgrade to Ubuntu 20.04

[Brad Buchanan]

While attempting to upgrade (with the GUI) I get this 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'.
"

It doesn't actually tell me what the problem is.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.42
ProcVersionSignature: Ubuntu 5.3.0-7648.41~1586790036~18.04~600aeb5~dev-generic 5.3.18
Uname: Linux 5.3.0-7648-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.23
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Sat Feb 6 22:02:54 2021
InstallationDate: Installed on 2018-08-26 (896 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/usr/bin/zsh
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2021-02-07 (0 days ago)
VarLogDistupgradeTermlog:

[Brad Buchanan (bradley-c-buchanan)]

My /var/log/dist-upgrade/main.log ends:

2021-02-06 22:02:23,299 WARNING Can't mark 'ubuntu-desktop' for upgrade (E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.)

Am I supposed to somehow remove/disable ubuntu-desktop before I can upgrade?

[Brian Murray (brian-murray)]

Reviewing the files from your upgrade attempt you seem to have enabled a PPA that provides Xorg packages. This will prevent the upgrade as that PPA contains package version numbers greater than the release to which you are upgrading. You can revert the PPA by installing the ppa-purge package from the official Ubuntu archive and then running 'sudo ppa-purge ppa:kisak/kisak-mesa'. After that you can try upgrading again and if it still fails open a new bug report. Thanks and good luck!