[Bug 1533908] [NEW] error when upgrading from v14.04 to v15 -- always receiving msg panel stating: "Could not calculate the upgrade". None of the 3 causes listed apply

[dan3city]

Public bug reported:

have attempted the upgrade every 2-3 days for the past two weeks.   have
applied other maintenance than was available.   this is a simple,
unmodified Ubuntu 14.04 image installed from the Ubuntu site download in
Dec, 2015.  Operating on a Lenovo T500 laptop.

Ubuntu 14.04.3 LTS  release 14.04

I get the exact same error each time.   First a warning message that
"some download sources are disabled" (no info about which sources and I
only use the options of the SW installer).   Then upgrade proceeds until
the "Unable to Calculate" panel is given.  Then the upgrade process is
backed-out.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.13.0-74.118-generic 3.13.11-ckt30
Uname: Linux 3.13.0-74-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Wed Jan 13 16:13:15 2016
InstallationDate: Installed on 2014-07-05 (557 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2016-01-14 (0 days ago)
VarLogDistupgradeTermlog:
 
mtime.conffile..etc.update.manager.release.upgrades: 2016-01-01T12:41:32.353555

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


** Tags: amd64 apport-bug dist-upgrade trusty

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https://bugs.launchpad.net/bugs/1533908

Title:
  error when upgrading from v14.04 to v15 -- always receiving msg panel
  stating:  "Could not calculate the upgrade".  None of the 3 causes
  listed apply

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

Bug description:
  have attempted the upgrade every 2-3 days for the past two weeks.
  have applied other maintenance than was available.   this is a simple,
  unmodified Ubuntu 14.04 image installed from the Ubuntu site download
  in Dec, 2015.  Operating on a Lenovo T500 laptop.

  Ubuntu 14.04.3 LTS  release 14.04

  I get the exact same error each time.   First a warning message that
  "some download sources are disabled" (no info about which sources and
  I only use the options of the SW installer).   Then upgrade proceeds
  until the "Unable to Calculate" panel is given.  Then the upgrade
  process is backed-out.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: ubuntu-release-upgrader-core 1:0.220.8
  ProcVersionSignature: Ubuntu 3.13.0-74.118-generic 3.13.11-ckt30
  Uname: Linux 3.13.0-74-generic x86_64
  ApportVersion: 2.14.1-0ubuntu3.19
  Architecture: amd64
  CrashDB: ubuntu
  CurrentDesktop: Unity
  Date: Wed Jan 13 16:13:15 2016
  InstallationDate: Installed on 2014-07-05 (557 days ago)
  InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to trusty on 2016-01-14 (0 days ago)
  VarLogDistupgradeTermlog:
   
  mtime.conffile..etc.update.manager.release.upgrades: 2016-01-01T12:41:32.353555

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