An unresolvable problem occurred while calculating the upgrade

[peacecop kalmer:]

I want to upgrade from "23.10" to "24.04" and I get this log:

"<pre>Checking package manager
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done

Calculating the changes

Calculating the changes

Could not calculate 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 &apos;ppa-purge&apos; 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 &apos;ubuntu-bug ubuntu-release-upgrader-core&apos; in a terminal. If
you want to investigate this yourself the log files in
&apos;/var/log/dist-upgrade&apos; will contain details about the upgrade.
Specifically, look at &apos;main.log&apos; and &apos;apt.log&apos;.

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done</pre>"

ProblemType: Bug
DistroRelease: Ubuntu 23.10
Package: ubuntu-release-upgrader-core 1:23.10.14
ProcVersionSignature: Ubuntu 6.5.0-35.35-generic 6.5.13
Uname: Linux 6.5.0-35-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.27.0-0ubuntu5
Architecture: amd64
CasperMD5CheckResult: unknown
CrashDB: ubuntu
CurrentDesktop: XFCE
Date: Sat Jun 1 17:13:34 2024
InstallationDate: Installed on 2020-07-07 (1425 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to mantic on 2024-06-01 (0 days ago)
VarLogDistupgradeAptHistorylog:
 Start-Date: 2024-06-01 17:11:01
 Requested-By: kalmer (1000)
 End-Date: 2024-06-01 17:11:01
VarLogDistupgradeApttermlog:
 Log started: 2024-06-01 17:11:01
 Log ended: 2024-06-01 17:11:01