Comment 2 for bug 773823

I worked out what happened. When upgrading my systems to 10.10, it automatically added the following line to my sources.list without me realizing:

deb http://extras.ubuntu.com/ubuntu maverick main #Third party developers repository

When doing an upgrade, it decided that there was at least one official source, so wasn't going to let me do the rewrite step.

The work around was to comment out this line.

Brian May