[Bug 1685384] Re: Tried to upgrade to 17.04 from 16.10. It is not a clean installation and had been upgraded several times before, so maybe there is the reason. I'll try my best to figure it out.

[Brian Murray]

*** This bug is a duplicate of bug 1069133 ***
    https://bugs.launchpad.net/bugs/1069133

Reviewing the files from your upgrade attempt you seem to have enabled a
PPA that provides Xorg packages. This will prevent the upgrade as that
PPA contains different versions of packages essential to Ubuntu.  The
page, https://launchpad.net/~xorg-edgers/+archive/ppa, contains details
on to how to revert to the official Xorg packages for the xorg-edgers
PPA.  Instructions for reverting to official Xorg packages should be
similar for the PPA that you have enabled.

** Changed in: ubuntu-release-upgrader (Ubuntu)
       Status: New => Invalid

** Tags added: ppa xorg-edgers-ppa

** This bug has been marked a duplicate of bug 1069133
   Get upgrade error 12.04 - 12.10 "Could not determine upgrade" - xorg from ppa

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https://bugs.launchpad.net/bugs/1685384

Title:
  Tried to upgrade to 17.04 from 16.10. It is not a clean installation
  and had been upgraded several times before, so maybe there is the
  reason. I'll try my best to figure it out.

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

Bug description:
  1
  Description:	Ubuntu 16.10
  Release:	16.10

  2
  Unable to locate package pkgname
  No wonder, tried a distribution update

  3
  The updater should have updated my system automatically from 16.10 to 17.04

  4
  Could not calculate the upgrade

  An unresolvable problem occurred while calculating the upgrade.

   This can be caused by:
   * Upgrading to a pre-release version of Ubuntu
   * Running the current pre-release version of Ubuntu
   * Unofficial software packages not provided by Ubuntu

  If none of this applies, then please report this bug using the command
  'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.

  ProblemType: Bug
  DistroRelease: Ubuntu 16.10
  Package: ubuntu-release-upgrader-core 1:16.10.10
  ProcVersionSignature: Ubuntu 4.8.0-49.52-generic 4.8.17
  Uname: Linux 4.8.0-49-generic x86_64
  ApportVersion: 2.20.3-0ubuntu8.2
  Architecture: amd64
  CrashDB: ubuntu
  CurrentDesktop: GNOME
  Date: Sat Apr 22 00:58:49 2017
  InstallationDate: Installed on 2015-03-17 (766 days ago)
  InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to yakkety on 2017-04-21 (0 days ago)
  VarLogDistupgradeTermlog:

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