Update 14.10 to 15.04 failed - Unsolvable while calculating upgrade

[Dillon]

Ubuntu Release:
:~$ lsb_release -rd
Description: Ubuntu 14.10
Release: 14.10

Version of Package:
:~$ apt-cache policy pkgme
pkgme:
  Installed: (none)
  Candidate: 0.1+bzr114
  Version table:
     0.1+bzr114 0
        500 http://us.archive.ubuntu.com/ubuntu/ vivid/universe amd64 Packages

Expected:
When option to Upgrade to 15.04 was available and after selecting the upgrade button, I expected package upgrade to occur as it is listed as supported in: http://ubuntugnome.org/ubuntu-gnome-15-04-is-released/

What actually happened:
Upgrade went through preparations during upgrade to check, which successfully completes. Provides warning about 3rd party entries, which is fine. Preparing to upgrade completes successfully. Starts download for new software channels of 53, which appears to complete successfully, but error occurs shortly after 'checking package manager'. It then throws error:
Could not calculate the upgrade
An unresolvable problem occurred while calculating the upgrade.
[List of what its caused by]
[How to report if none apply]

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: ubuntu-release-upgrader-core 1:14.10.10
ProcVersionSignature: Ubuntu 3.16.0-37.51-generic 3.16.7-ckt9
Uname: Linux 3.16.0-37-generic x86_64
ApportVersion: 2.14.7-0ubuntu8.4
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: GNOME
Date: Thu May 7 20:46:19 2015
InstallationDate: Installed on 2015-03-27 (41 days ago)
InstallationMedia: Ubuntu-GNOME 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to utopic on 2015-05-08 (0 days ago)
VarLogDistupgradeTermlog:

[Dillon (dtorgersen86)]

I failed to mention that I am using Ubuntu Gnome as well.

[Brian Murray (brian-murray)]

Reviewing the files from your upgrade attempt you seem to have enabled a PPA that provides Xorg packages. 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 for the xorg-edgers PPA. Instructions for reverting to official Xorg packages should be similar for the PPA that you have enabled.