Upgrade to unity stops with "Can not calculate the upgrade"

[Stephan Schaefer]

Stop at calculating upgrade

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.5
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Sat Nov 1 17:35:20 2014
InstallationDate: Installed on 2014-08-15 (78 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64+mac (20140417)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
SystemImageInfo: Error: command ['system-image-cli', '-i'] failed with exit code 1:
UpgradeStatus: Upgraded to trusty on 2014-11-01 (0 days ago)
VarLogDistupgradeTermlog:

mtime.conffile..etc.update.manager.release.upgrades: 2014-08-17T20:09:34.261833