Just got my 1st CTD.
I had turned up the setting to ultra and was getting a steady 30fps. Walking to Whiterun from Riverwood. Got to the farms outside Whiterun and a storm started rolling in....
Desktop.
Possibly my own fault for pushing my hardware. Will put back to the recommended (high) settings and test again.
Clocked up 11hrs playtime so far. And loved every minute, until it crashed.