Comment 13 for bug 909926

I am also seeing this and can confirm that it appears with both Nouveau and Nvidia propritary drivers.
For me it is a bit of less serious, since the corrupted screen content goes away after a few seconds and the Unity desktop is shown properly afterwards.

I also took a photo with my camera of the screen during login (directly after entering my password) which I'm attaching here. Note that the screen obviously shows a random dump of previous content of the graphic card memory, some parts even contain "screenshots" of my previous Oneiric session where I downloaded the Precise daily image and prepared my pen drive (three or four reboots ago!).

Kind regards,
Jan