Upgrade from v18 LTS to 20.04.1 LTS doesn't work both via shell and using upgrade manager

[Paul]

Was experiencing 2 issues. The first one is resolved but may be related to the one currently being faced, hence why I'm sharing it:

Issue 1) Software-Updater prompts to upgrade to 20.04.1 LTS but clicking on upgrade causes the dialog box to disappear and does nothing in the background. After following the steps highlighted below this paragraph, I found that wine wasn't getting updated for some reason, so I readded the PPAs for that and updated it via shell. This resolved the issue and upon a restart, the Software-Updater upgrade to 20.04.1 LTS started going to the actual upgrade screen upon clicking upgrade.

sudo apt update
sudo apt upgrade
sudo reboot command (up till this, upgraded everything except wine)

To fix wine:
sudo dpkg --add-architecture i386
wget -qO - https://dl.winehq.org/wine-builds/winehq.key | sudo apt-key add -
sudo add-apt-repository ppa:cybermax-dexter/sdl2-backport
sudo apt update
sudo apt upgrade
sudo reboot command

Doing the above upgraded wine to v5 from v4 and allowed me to proceed to Issue 2 below.

Issue 2) Software-Updater fails at the 2nd step during upgrade and generates the error in the attached screenshot. I disabled all third party ppas by going to the "Software & Updates" tool, clicked on "Other Software" and disabled anything that had a checkmark to it (namely the kisak-mesa/bionic ppa and the google chrome ppa, there was one other but I can't recall which one anymore), restarted, and ran again. This did not fix the overall issue but the prompt mentioning 3rd party ppas as a possible cause no longer shows up in the dialog box and only suggests filing a bug.

I also tried using sudo do-release-upgrade and it generates the exact same error as using the GUI interface. All packages are up to date and nothing is identified as possible packages left to update, third party or otherwise. I also don't see unnecessary packages sitting on the system.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.38
ProcVersionSignature: Ubuntu 4.15.0-118.119-generic 4.15.18
Uname: Linux 4.15.0-118-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.17
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Wed Sep 30 22:15:34 2020
InstallationDate: Installed on 2017-10-25 (1071 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-10-01 (0 days ago)

Edit: Added additional details for Issue 1 as my resolution steps were incredibly vague. Also added details on exactly where I went to disable the third party ppas and what ppas I recall disabling.

[Brian Murray (brian-murray)]

It is not enough to disable the third party PPAs as you've done, rather you need to use the tool ppa-purge to disable those PPAs and install the official versions of the packages the PPA provides. So please re-enable the mesa PPA and then use ppa-purge to switch to the official Ubuntu packages and try the upgrade again. Thanks and good luck!

[Launchpad Janitor (janitor)]

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