I couldn’t boot into Unity after upgrades last night. Fortunately I didn’t need the lappy for the meeting I was heading to.
22 tabs later, I figured out the issue. Basically, the nvidia module loaded in the kernel was different from the driver I has installed, causing the “NVIDIA API MISMATCH” error. I don’t have the entire error, but it shows the two versions that are different, in my case they were 3.19 and 3.04. I don’t care, it shouldn’t have happened, I am bitter at the moment.
Here’s how I solved it.
From 12.04.1 partial upgrade broke X:
sudo apt-get purge nvidia*
sudo apt-get install nvidia-current-updates-dev
sudo reboot
That got me to the login screen, but when I tried logging in it would flash to the nvidia logo, go black, and load the login screen again. I had read about this, and soon found Kicked back to login screen when logging in:
sudo rm ~/.Xauthority
sudo service lightdm restart
And it works again. What is .Xauthority? I don’t care.