Could not upgrade from Pangolin to 14.04

[Adam Buckley]

Ubuntu 12.04 LTS

Entered password (which was accepted)

Upgrading Ubuntu to version 14.04
- Preparing to upgrade (done!)
- Setting new software channels (error)

Could not calculate the upgrade: An unresolvable problem occurred while calculating the upgrade.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.17
ProcVersionSignature: Ubuntu 3.13.0-32.57~precise1-generic 3.13.11.4
Uname: Linux 3.13.0-32-generic i686
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
Date: Tue Aug 12 08:31:15 2014
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1407856841
 com.ubuntu.update-manager window-height 518
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04.2 LTS "Precise Pangolin" - Release i386 (20130213)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_CA:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_CA.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-08-12 (0 days ago)
VarLogDistupgradeTermlog:

[Brian Murray (brian-murray)]

This is because you've enabled a PPA which provides blender that depends on a version of python3 which is greater than the version of python3 in Trusty. You'll need to use the tool ppa-purge to remove this PPA for the upgrade to proceed.

2014-09-29 15:20:29,725 DEBUG examining: 'deb http://ppa.launchpad.net/irie/blender/ubuntu precise main'