Errore upgrade 18.04 LTS a 20.04 LTS AMD64

[Massimo Davio]

Si è verificato un problema irresolubile durante il calcolo dell'avanzamento.

 Nel caso fosse un altro problema, segnalare un bug eseguendo in un terminale il seguente comando: «ubuntu-bug ubuntu-release-upgrader-core». Per investigare il problema consultare i file di registro in «/var/log/dist-upgrade» che possono contenere maggiori dettagli riguardo all'avanzamento. In particolare, consultare i file «main.log» e «apt.log».

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.33
ProcVersionSignature: Ubuntu 4.15.0-54.58-generic 4.15.18
Uname: Linux 4.15.0-54-generic x86_64
NonfreeKernelModules: lkp_Ubuntu_4_15_0_54_58_generic_59
ApportVersion: 2.20.9-0ubuntu7.6
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Thu Nov 5 18:09:43 2020
InstallationDate: Installed on 2017-09-01 (1161 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-11-05 (0 days ago)
VarLogDistupgradeTermlog:

[Launchpad Janitor (janitor)]

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

[Egidio Quadrini (photer)]

Da /var/log/dist-upgrade/20201205-1836/main.log
.....
2020-12-05 18:22:26,728 INFO checking for python-dbg
2020-12-05 18:22:26,728 INFO installing python2-dbg because python-dbg was installed
2020-12-05 18:22:26,728 DEBUG Installing 'python2-dbg' (python-dbg was installed on the system)
2020-12-05 18:22:27,009 ERROR Dist-upgrade failed: 'E:Errore, pkgProblemResolver::Resolve ha generato delle interruzioni. Questo potrebbe essere causato da pacchetti bloccati.'
2020-12-05 18:22:27,010 DEBUG abort called
2020-12-05 18:22:27,011 DEBUG openCache()
2020-12-05 18:22:29,703 DEBUG Comparing 4.15.0-124 with
2020-12-05 18:22:29,703 DEBUG Comparing 4.15.0-126 with 4.15.0-124
2020-12-05 18:22:29,974 DEBUG /openCache(), new cache size 100873