Could not determine 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... Done
Reading state information... Done
When I look in the main.log I see the following error
2025-05-01 18:49:40,745 ERROR Dist-upgrade failed: 'E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.'
john@UbuntuPlex:~$ sudo apt full-upgrade
[sudo] password for john:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.
Probably. It’s one step to returning your system to close to stock condition.
One assumes your data is properly backed up before starting a release-upgrade.
Now does your release-upgrade work?
Now it gets more complex and time-consuming. The problem is most commonly something you installed from among those many non-Ubuntu sources. Or perhaps something you removed.
The typical troubleshooting from here involves iteration: Review the apt log, uninstall non-Ubuntu software, disable a non-Ubuntu source, try the release-upgrade again. Rinse and repeat for each non-Ubuntu source. At some point you will uninstall whatever you originally installed that is causing the problem. Maybe you get it on the first try if you are handy at reading the log. Maybe not.
This is, of course, very much what your original output suggested:
Decision Point: How much time and effort are you willing to invest before reinstalling becomes an attractive option?