Cannot upgrade 18.04 to 20.04

[Sean Meacher]

So I'm trying to upgrade my storage machine (which I also use as a remote desktop) from 18.04 to 20.04 and the upgrader is failing.

/var/log/dist-upgrade mentions
2020-10-31 12:25:37,733 INFO installing python-is-python2 because python-minimal was installed
2020-10-31 12:25:37,733 DEBUG Installing 'python-is-python2' (python-minimal was installed on the system)
2020-10-31 12:25:37,981 ERROR Dist-upgrade failed: 'E:Unable to correct problems, you have held broken packages.'

There aren't any held/broken packages.

It seems a similar issue to this (with the mention of python-is-python2)
https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1875523
but the upgrader is already on 20.04.28

I did have this ppa installed for some reason ppa:ubuntu-toolchain-r/test but removed that as one of the first troubleshooting steps (and then had to copy a lib file from another machine to fix apt...).

But basically, is it something I've done or is it the upgrader?

Thanks,
Sean

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.40
ProcVersionSignature: Ubuntu 4.15.0-122.124-generic 4.15.18
Uname: Linux 4.15.0-122-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.9-0ubuntu7.18
Architecture: amd64
CrashDB: ubuntu
Date: Sat Oct 31 12:26:08 2020
InstallationDate: Installed on 2011-12-26 (3231 days ago)
InstallationMedia: Ubuntu-Server 10.04.3 LTS "Lucid Lynx" - Release amd64 (20110719.2)
PackageArchitecture: all
ProcEnviron:
 LD_LIBRARY_PATH=<set>
 TERM=screen-256color-bce
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-10-31 (0 days ago)
VarLogDistupgradeAptclonesystemstate.tar.gz:
 Error: command ['pkexec', 'cat', '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'] failed with exit code 127: polkit-agent-helper-1: error response to PolicyKit daemon: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: No session for cookie
 Error executing command as another user: Not authorized

 This incident has been reported.

[Sean Meacher (sean-gongbong)]

main.log from upgrader if it didn't automatically attach

[Sean Meacher (sean-gongbong)]

apt.log from upgrader if it didn't automatically attach

[Sean Meacher (sean-gongbong)]

can't add this directly, so adding via dropbox
https://www.dropbox.com/s/vmu3ndr7zwbobrp/apt-clone_system_state.tar.gz?dl=0

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Nevyn (nevynh)]

Ran the following script to find any packages that had been installed from other sources and removed them all.

#!/bin/sh

# Print packages installed from different origins.
# Exclude standard Ubuntu repositories.

grep -H '^Origin:' /var/lib/apt/lists/*Release | grep -v ' Ubuntu$' | sort -u \
| while read -r line; do
    origin=${line#* }
    echo $origin:

    list=${line%%:*}
    sed -rn 's/^Package: (.*)$/\1/p' ${list%_*Release}*Packages | sort -u \
    | xargs -r dpkg -l 2>/dev/null | grep '^.i '
    echo
 done