Comment 0 for bug 753755

when executing update-manager -d
an error systematically occurs at the stage where the manager says calculating changes or something like that
I get this message :
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

I am joining the /var/log/dist-upgrade for my latest attempt