Cannot dist-upgrade from 14.04 to 15.04

[Max Małecki]

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

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
NonfreeKernelModules: fglrx
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Sat Jan 16 12:15:25 2016
InstallationDate: Installed on 2014-12-24 (387 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2016-01-16 (0 days ago)
mtime.conffile..etc.update.manager.release.upgrades: 2016-01-16T11:44:46.201354

[Brian Murray (brian-murray)]

From Mainlog.txt:

016-01-16 12:14:53,535 DEBUG plugins for condition 'from_trustyPostDistUpgradeCache' are '[]'
2016-01-16 12:14:53,536 DEBUG none of the '['ubuntu-desktop', 'kubuntu-desktop', 'xubuntu-core', 'xubuntu-desktop', 'ubuntustudio-desktop', 'mythbuntu-desktop', 'kubuntu-netbook', 'lubuntu-core', 'lubuntu-desktop', 'ubuntu-gnome-desktop']' meta-pkgs installed
2016-01-16 12:14:53,536 DEBUG guessing 'ubuntu-desktop' as missing meta-pkg
2016-01-16 12:14:55,338 ERROR failed to mark 'ubuntu-desktop' for install (E:Unable to correct problems, you have held broken packages.)

Please install one of the supported meta-pkgs listed and try the upgrade again.

[Brian Murray (brian-murray)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1534374, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.