Could not calculate the upgrade An unresolvable problem occurred while calculating the upgrade.

[Philippe Quintard]

Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade.

Removed other PPAs in "Other Software" in Software & Updates

How do I find out which package I need to remove?

From main.log

2019-11-10 11:28:25,855 DEBUG entry 'deb http://security.ubuntu.com/ubuntu disco-security universe' updated to new dist
2019-11-10 11:28:25,855 DEBUG examining: 'deb http://security.ubuntu.com/ubuntu bionic-security multiverse'
2019-11-10 11:28:25,855 DEBUG entry 'deb http://security.ubuntu.com/ubuntu disco-security multiverse' updated to new dist
2019-11-10 11:28:25,858 DEBUG running doUpdate() (showErrors=True)
2019-11-10 11:28:51,559 DEBUG openCache()
2019-11-10 11:28:52,174 DEBUG /openCache(), new cache size 95639
2019-11-10 11:28:52,174 DEBUG need_server_mode(): run in 'desktop' mode, (because of pkg 'ubuntu-desktop')
2019-11-10 11:29:02,759 ERROR Dist-upgrade failed: 'E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.'
2019-11-10 11:29:02,761 DEBUG abort called
2019-11-10 11:29:02,763 DEBUG openCache()
2019-11-10 11:29:05,143 DEBUG /openCache(), new cache size 94778

From apt.log

Broken snmp:amd64 Depends on libsnmp30:amd64 < 5.7.3+dfsg-1.8ubuntu3.3 | 5.7.3+dfsg-5ubuntu1.2 @ii umH > (= 5.7.3+dfsg-5ubuntu1.2)
  Considering libsnmp30:amd64 13 as a solution to snmp:amd64 1
  MarkKeep snmp:amd64 < 5.7.3+dfsg-1.8ubuntu3.3 -> 5.7.3+dfsg-5ubuntu1.2 @ii umU Ib > FU=0
  Holding Back snmp:amd64 rather than change libsnmp30:amd64

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.34
ProcVersionSignature: Ubuntu 5.0.0-32.34~18.04.2-generic 5.0.21
Uname: Linux 5.0.0-32-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.9
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Sun Nov 10 11:08:54 2019
InstallationDate: Installed on 2019-05-26 (168 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2019-11-10 (0 days ago)
VarLogDistupgradeTermlog:

mtime.conffile..etc.update-manager.release-upgrades: 2019-10-25T19:22:11.427009

[Chippo Elder (chiphog)]

I had the same problem. I carefully pruned away all PPAs and the software installed from them. I did this by using software-properties-gtk and disabling all the repositories in 'Other Software' and then using aptitude to delete all packages in 'Obsolete or Local Packages'. However, this did not help.

While digging around in /var/log/dist-upgrade/apt.log (or was it main.log?), I saw that there were some packages that were identified as 'meta packages' and there were dependency resolution issues with some of these. These were:
xubuntu-desktop
ubuntu-unity-desktop
ubuntu-gnome-desktop
kubuntu-desktop
ubuntu-budgie-desktop
ubuntu-mate-desktop
lubuntu-desktop
Since I only need 1 of these to have a working system after the upgrade, I deleted them (except kubuntu-desktop and ubuntu-unity-desktop, I think), upgraded and then re-installed them.

[Launchpad Janitor (janitor)]

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