Following the upgrade using Update Manager, reboot, and GDM login, the desktop is solid white with no visible panels, icons, etc. Just white. The desktop is active - clicking in the menu bar causes disk activity.
I can shutdown the machine by pressing the hardware power button for two seconds, waiting a few more, and hitting Enter - the Shutdown dialog was posted and active but not visible. The desktop background appears for a fraction of a second at the start of the shutdown sequence. After powering-on again the graphical boot and login sequences go normally and again the white desktop. Repeatable. The machine is a Toshiba M2 laptop with an Nvidia GForce FX 5200 graphic chip. I installed the 173 legacy driver sometime back as mentioned in the 2008.11 release notes, and upgraded it to the latest version (173.14.18) prior to the upgrade. This doesn't appear to be a X failure as I can see the graphical login and the desktop background appears momentarily at the start of the shutdown sequence. Any thoughts? Frank
