Upgrade-option there but not available on Install wizard

[Johan Wysneus]

When I tried to upgrade from Ubuntu 13.10 to 14.04, the upgrade option was there but not available (greyed out). In the end I had to backup all my data first and then install Ubuntu 14.04 from scratch (which deleted all data on disk).

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.2
ProcVersionSignature: Ubuntu 3.13.0-34.60-generic 3.13.11.4
Uname: Linux 3.13.0-34-generic i686
ApportVersion: 2.14.1-0ubuntu3.3
Architecture: i386
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Mon Aug 18 21:23:52 2014
InstallationDate: Installed on 2014-05-24 (86 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release i386 (20131016.1)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: dist-upgrade
UpgradeStatus: Upgraded to trusty on 2014-05-24 (86 days ago)
VarLogDistupgradeTermlog:

modified.conffile..etc.update.manager.release.upgrades: [modified]
mtime.conffile..etc.update.manager.release.upgrades: 2014-05-25T11:04:20.171257