Upgrade from 18.04 to 20.04 failed

[Justus Schlichting]

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'.

From main.log ...
2021-05-17 16:31:04,840 INFO checking for python-dbg (auto_inst=False)
2021-05-17 16:31:04,840 INFO checking for python-doc (auto_inst=False)
2021-05-17 16:31:04,840 INFO checking for python-minimal (auto_inst=False)
2021-05-17 16:31:04,840 INFO installing python-is-python2 because python-minimal was installed
2021-05-17 16:31:04,840 DEBUG Installing 'python-is-python2' (python-minimal was installed on the system)
2021-05-17 16:31:04,900 INFO removing python-minimal because python-is-python2 is being installed
2021-05-17 16:31:04,900 DEBUG Removing 'python-minimal' (python-is-python2 is being installed on the system)
2021-05-17 16:31:04,956 INFO failed to remove python-minimal
2021-05-17 16:31:04,957 INFO checking for python-dev (auto_inst=False)
2021-05-17 16:31:04,957 INFO checking for libpython-dev (auto_inst=False)
2021-05-17 16:31:04,957 INFO checking for libpython-stdlib (auto_inst=False)
2021-05-17 16:31:04,957 INFO removing libpython-stdlib because None is being installed
2021-05-17 16:31:04,957 DEBUG Removing 'libpython-stdlib' (None is being installed on the system)
2021-05-17 16:31:05,013 INFO failed to remove libpython-stdlib
2021-05-17 16:31:05,013 INFO checking for libpython-dbg (auto_inst=False)
2021-05-17 16:31:05,013 INFO checking for python-dbg (auto_inst=True)
2021-05-17 16:31:05,013 INFO checking for python-doc (auto_inst=True)
2021-05-17 16:31:05,013 INFO checking for python-minimal (auto_inst=True)
2021-05-17 16:31:05,013 INFO installing python-is-python2 because python-minimal was installed
2021-05-17 16:31:05,014 DEBUG Installing 'python-is-python2' (python-minimal was installed on the system)
2021-05-17 16:31:05,073 INFO removing python-minimal because python-is-python2 is being installed
2021-05-17 16:31:05,073 DEBUG Removing 'python-minimal' (python-is-python2 is being installed on the system)
2021-05-17 16:31:05,073 INFO failed to remove python-minimal
2021-05-17 16:31:05,073 INFO checking for python-dev (auto_inst=True)
2021-05-17 16:31:05,073 INFO checking for libpython-dev (auto_inst=True)
2021-05-17 16:31:05,073 INFO checking for libpython-stdlib (auto_inst=True)
2021-05-17 16:31:05,073 INFO removing libpython-stdlib because None is being installed
2021-05-17 16:31:05,073 DEBUG Removing 'libpython-stdlib' (None is being installed on the system)
2021-05-17 16:31:05,074 INFO failed to remove libpython-stdlib
2021-05-17 16:31:05,074 INFO checking for libpython-dbg (auto_inst=True)
2021-05-17 16:37:47,739 ERROR Dist-upgrade failed: 'E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.'
2021-05-17 16:37:47,745 DEBUG abort called
2021-05-17 16:37:47,748 DEBUG openCache()
2021-05-17 16:37:51,388 DEBUG Comparing 3.11.0-26 with
2021-05-17 16:37:51,389 DEBUG Comparing 3.13.0-109 with 3.11.0-26
2021-05-17 16:37:51,389 DEBUG Comparing 3.13.0-165 with 3.13.0-109
2021-05-17 16:37:51,390 DEBUG Comparing 3.13.0-96 with 3.13.0-165
2021-05-17 16:37:51,390 DEBUG Comparing 3.8.0-32 with 3.13.0-165
2021-05-17 16:37:51,396 DEBUG Comparing 4.15.0-142 with 3.13.0-165
2021-05-17 16:37:51,396 DEBUG Comparing 4.15.0-143 with 4.15.0-142
2021-05-17 16:37:51,845 DEBUG /openCache(), new cache size 104343

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.44
ProcVersionSignature: Ubuntu 4.15.0-143.147-generic 4.15.18
Uname: Linux 4.15.0-143-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.23
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Mon May 17 17:04:14 2021
InstallationDate: Installed on 2013-05-10 (2929 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
PackageArchitecture: all
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
 PATH=(custom, no user)
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2021-05-18 (0 days ago)
VarLogDistupgradeTermlog:

[Brian Murray (brian-murray)]

Thanks for taking the time to report this upgrade failure. There is currently a new version of the release upgrader available in -proposed which may resolve the error you've encountered. Please run the following command to test the new version of the upgrader:

  do-release-upgrade -p

Please lets us know the results in this bug report. Thanks again and good luck!

[Justus Schlichting (justusjay)]

Thank you, Brian. The new version of the release upgrader resolved the problem. I am happily on 20.04 now.