cannot update to 14.04 from 12.04

[Alexie]

Update-manager tells me that I cannot upgrade to 14.04 (something about cannot determine the sources?)

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.17
ProcVersionSignature: Ubuntu 3.5.0-44.67~precise1-generic 3.5.7.25
Uname: Linux 3.5.0-44-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.7
Architecture: amd64
Date: Sun Sep 21 18:17:26 2014
GsettingsChanges:
 com.ubuntu.update-manager check-new-release-ignore 'trusty'
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1411287291
 com.ubuntu.update-manager window-height 600
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-09-21 (0 days ago)
VarLogDistupgradeTermlog:

[Alexie (alpapan)]

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done
Building data structures... Done

Calculating the changes

Calculating the changes

Could not determine 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.

I tried this 3-4 times. I disabled all non-canonical ubuntu repos in /etc/apt/sources.d/*