I just did a normal upgrade of suggested security patches that included a kernel update. I typically run dual monitors using "Twinview" that allows me to drag windows from one monitor to another.

After the upgrade, the drivers refuse to recognize the second monitor. I've swapped cables and both monitors work, but even after swapping it defaults back to the right hand screen. The NVidia control panel swears that I only have one screen attached.

I've tried restoring my xorg.conf file from backup, blowing it away entirely and recreating it with the NVidia tool and manually editing it by hand all to no avail. Something seems to have broken twinview in the new updates.

Very frustrating...

Update...

Turns out the monitor cable was at fault - the cable fine after swapping to the other port, but it wouldn't detect that the monitor was there when things were started up. Weird that it didn't occur until a reboot.