There was a hidden in /lib/linux-restricted-modules/ that confused Xorg byt thinking it had the wrong driver version.
I ran: sudo rm /lib/linux-restricted-modules/.nvidia* and it fixed that problem.
The second problem was that GLX and Direct Rendering wouldn't load. That was caused by the XGL package still being installed.
I removed all XGL packages and the problem was solved.
I suggest that the update script should check for both of these problems, as it will probably be very common for people upgrading from Feisty to Gusty!
It seems the problem was two fold:
There was a hidden in /lib/linux- restricted- modules/ that confused Xorg byt thinking it had the wrong driver version. restricted- modules/ .nvidia* and it fixed that problem.
I ran: sudo rm /lib/linux-
The second problem was that GLX and Direct Rendering wouldn't load. That was caused by the XGL package still being installed.
I removed all XGL packages and the problem was solved.
I suggest that the update script should check for both of these problems, as it will probably be very common for people upgrading from Feisty to Gusty!