Upgrade failure from 13.10 to 14.04 LTS

[theo wilde]

I disabled all extra ppa sources, but still no luck keep getting the error.

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.

And there is no error output what i can search for on the web.
Anybody know how i can get more data for troubleshooting purposes ?
Or is there some trick i can use to get the upgrade done?

Lsb_release
Description: Ubuntu 13.10
Release: 13.10

uname
Linux 3.11.0-26-generic #45-Ubuntu SMP Tue Jul 15 04:02:06 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: ubuntu-release-upgrader-core 1:0.205.6
ProcVersionSignature: Ubuntu 3.11.0-26.45-generic 3.11.10.12
Uname: Linux 3.11.0-26-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
CrashDB: ubuntu
Date: Fri Sep 19 17:41:26 2014
InstallationDate: Installed on 2013-11-07 (315 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to saucy on 2014-09-19 (0 days ago)