We’re hearing reports that there’s a bit of a bug in an update to Ubuntu 10.10 today that is leaving users on Intel in particular who are making use of Clutter-based apps and interfaces – e.g. Unity – with nothing but a white screen for entertainment.
A normal GNOME session still works and this, if you can get the GDM, will allow you to use your desktop as usual (sans the Unity interface, of course).
Neil J Patel offers up the following advice to users who already updated and are stuck with a messed up system:
1. Add "export CLUTTER_VBLANK=none" to /etc/environment (without the quotes)
2. Restart
We’ll let you know as soon as the coast is clear but for now if you’re worried/of a nervous disposition try not to update.