An unresolvable problem occurred while calculating the upgrade

[Amadu]

An unresolvable problem occurred while calculating the upgrade:
E:Unable to correct problems, you have held broken packages.

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 12.04
Package: update-manager 1:0.156.14.11
ProcVersionSignature: Ubuntu 3.2.0-37.58-generic 3.2.35
Uname: Linux 3.2.0-37-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: amd64
Date: Fri Feb 8 06:34:46 2013
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1360302666
 com.ubuntu.update-manager window-height 500
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120309)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2013-02-08 (0 days ago)
VarLogDistupgradeAptclonesystemstate.tar.gz: Error: [Errno 13] Permission denied: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'

[Brian Murray (brian-murray)]

Reviewing the files from your upgrade attempt you seem to have enabled the xorg-edgers-ppa. This will prevent the upgrade as that PPA contains different versions of packages essential to Ubuntu. The page, https://launchpad.net/~xorg-edgers/+archive/ppa, contains details on to how to revert to the official Xorg packages.