Comment 25 for bug 626974

I recently upgraded from 10.4 to 10.10 x64 and found out the hard way that 10.10 has issues with nVidia GeForce8400 due to newer version of Xorg 1.9. I had the nVidia driver 'current' working with my nVidia GeForce 8400 when I performed the upgrade from 10.4, and after rebooting found that the system booted to a purple background image with no login prompt. I tried booting into recovery mode by holding shift while booting and disabling the nVidia driver and rebooting.

Now with the driver removed the system boots to purple background screen with the ubuntu status indicators (dots) and makes the drum sound normally followed by the login prompt, but I'm unable to see it and none of the function keys work to drop to a console. However if I perform the reboot again with the drivers removed I'm able to hold down the shift key while booting and enter recovery mode again and then select safe graphics mode to access the system, and this seems to work ok, but I cannot get the system to boot without performing these manual steps.