Comment 22 for bug 463915

Warning: I am certainly not an expert in this topic and my advice should not be taken as definitive in this matter...

It is my understanding that changes in Gnome prevents the ability for live-switching that we have come to expect. Furthermore, it is looking like there are a number of different ways for the settings to be messed up that prevents a simple, sure-fire way to get back UNR desktop. I have inquired about this issue to others a while back and I haven't heard much more about it.

The only way I know of to recover UNR desktop is to create a new user. That user should have the normal UNR desktop. Then, you could transfer your files and most of your settings (like those in .mozilla and such). When happy with the transfer, you can then delete the old account. I would only recommend this for those who know what they are doing, though.