[Bug 1949242] [NEW] Purged all ppas but cannot do-release-upgrade from Xubuntu 16.04 to 18.04

[kursataker]

Public bug reported:

Description:	Ubuntu 16.04.7 LTS
Release:	16.04

I wanted to upgrade from Xubuntu 16.04 to 18.04. I purged all PPAs.

Still kept receiving this message when sudo do-release-upgrade:

...

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 'ppa-purge' 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 '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'. 

...

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.32
ProcVersionSignature: Ubuntu 4.15.0-24.26~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-24-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.30
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: XFCE
Date: Sat Oct 30 02:04:05 2021
InstallationDate: Installed on 2016-04-01 (2037 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to xenial on 2021-10-29 (0 days ago)

** Affects: ubuntu-release-upgrader (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug dist-upgrade third-party-packages xenial

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubuntu-release-upgrader in
Ubuntu.
https://bugs.launchpad.net/bugs/1949242

Title:
  Purged all ppas but cannot do-release-upgrade from Xubuntu 16.04 to
  18.04

Status in ubuntu-release-upgrader package in Ubuntu:
  New

Bug description:
  Description:	Ubuntu 16.04.7 LTS
  Release:	16.04

  I wanted to upgrade from Xubuntu 16.04 to 18.04. I purged all PPAs.

  Still kept receiving this message when sudo do-release-upgrade:

  ...

  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 'ppa-purge' 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 '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'. 

  ...

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: ubuntu-release-upgrader-core 1:16.04.32
  ProcVersionSignature: Ubuntu 4.15.0-24.26~16.04.1-generic 4.15.18
  Uname: Linux 4.15.0-24-generic x86_64
  ApportVersion: 2.20.1-0ubuntu2.30
  Architecture: amd64
  CrashDB: ubuntu
  CurrentDesktop: XFCE
  Date: Sat Oct 30 02:04:05 2021
  InstallationDate: Installed on 2016-04-01 (2037 days ago)
  InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to xenial on 2021-10-29 (0 days ago)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1949242/+subscriptions