Cannot upgrade ubuntu 12.04 precise to 14.04

[Mahdi Fattahi]

Trying to upgrade ubuntu 12.04 to the next LTS release I got the following 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

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.12
ProcVersionSignature: Ubuntu 3.2.0-60.91-generic-pae 3.2.55
Uname: Linux 3.2.0-60-generic-pae i686
ApportVersion: 2.0.1-0ubuntu17.7
Architecture: i386
Date: Fri Oct 24 17:00:58 2014
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1414157159
 com.ubuntu.update-manager window-height 500
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120301)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-10-24 (0 days ago)
VarLogDistupgradeAptclonesystemstate.tar.gz: Error: [Errno 13] Permission denied: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'

[Mahdi Fattahi (mfat)]

Problem fixed.

I ran the foolowing command to determine obsolete packages. After removing them, the upgrade succeeded.

$ cat /var/log/dist-upgrade/main.log | grep Obsolete

[Ubuntu Foundations Team Bug Bot (crichton)]

You seem to have installed the cinnamon package on Ubuntu 13.10. Unfortunately, that package is not available yet for 14.04. To upgrade to Ubuntu 14.04 LTS you'll need to either wait for a fix for cinnamon to be available or uninstall the package and then upgrade.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]