Ubuntu 8.04 LTS upgrade from 7.10 fails

[Steve Cook]

On Sun, 2008-04-27 at 16:05 -0400, Robert Stockdale IV wrote:
> I have Ubuntu Studio 7.10 installed on my workstation. When I go to
> upgrade to 8.04 LTS I get the error message:
> 
> Could not calculate the upgrade
> 
> A 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 against the
> 'update-manager' package and include the files
> in /var/log/dist-upgrade/ in the bugreport.
> 
> I do have ¨Unofficial software packages not provided by Ubuntu¨
> however, I don´t see how that should be an issue. If those packages
> don´t work after the upgrade then I will be required to reinstall
> them. It should not prevent me from using the upgrade tool to upgrade
> my system. It would be nice if there was a warning about this and an
> option to proceed or cancel the upgrade.
> Bob

Hi Bob,
I got a similar error message on one machine and resolved it on one
machine by running 

sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get clean

before upgrading to 8.04.

I haven't solved it on the other machine mind you.

SteVe