I can not upgrade 14.04 to 15.04

[Patrik]

patrik@patrik-UX305FA:~$ ubuntu-bug ubuntu-release-upgrader-core
patrik@patrik-UX305FA:~$
(exo-helper-1:5037): Gdk-CRITICAL **: IA__gdk_window_get_window_type: assertion 'GDK_IS_WINDOW (window)' failed
Ve stávající relaci prohlížeče bylo vytvořeno nové okno.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.19.0-41.46~14.04.2-generic 3.19.8-ckt10
Uname: Linux 3.19.0-41-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: XFCE
Date: Tue Dec 15 20:17:19 2015
InstallationDate: Installed on 2015-11-29 (16 days ago)
InstallationMedia: Xubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2015-12-15 (0 days ago)
VarLogDistupgradeTermlog:

mtime.conffile..etc.update.manager.release.upgrades: 2015-11-29T11:31:45.967459

[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.