The error message I get on trying to upgrade is
Could not determine the upgrade
An unresolvable problem occurred while calculating the upgrade:
E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.
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
If none of this applies, then please report this bug against the 'update-manager' package and include the files in /var/log/dist-upgrade/ in the bug report.
Following the advice in another forum posting I have already tried
sudo apt-get remove xserver-xorg-video-nouveau but this has not helped. What now? Should I report a bug?