the upgrade stops with the message:
>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.
>
In addition, the bug reporting tool also crashes.
None of the suggested causes apply. No further information is available.
After running:
sudo do-release-upgrade
the upgrade stops with the message:
>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 release- upgrader- core' in a terminal.
command 'ubuntu-bug ubuntu-
>
In addition, the bug reporting tool also crashes.
None of the suggested causes apply. No further information is available.