Untitled

Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade:
E:Unable to correct problems, you have held broken 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 using the
command 'ubuntu-bug update-manager' in a terminal.


Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
Building data structures... Done