An unresolvable problem occurred while calculating the upgrade:
The package 'unity' is marked for removal but it is in the removal blacklist. 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.
What shall i do? Do i need to remove untiy from blacklist but how?