Unable to upgrade from 14.04 to 16.04. I'm trying sudo do-release-upgrade
and it fails with the following error:
Calculating the changes
Could not calculate the upgrade
An unresolvable problem occurred while calculating the upgrade.
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 ubuntu-release-upgrader-core' in a terminal.
Restoring original system state
/var/log/dist-upgrade/main.log https://www.dropbox.com/s/3gf1tg8uxmn75jq/main.log?dl=0 /var/log/dist-upgrade/apt.log https://www.dropbox.com/s/79i2mf320pvg3bl/apt.log?dl=0
I don't understand why package manager can not resolve this and what package is the source of this problem.
Appreciate any help.