I have a user, that says he gets this error, about 50% of the time, when he closes NX at the end of the day. He's using a mobile workstation, over wifi most of the time. Everything I found in the Solution Center, referred to Camstar, which we do not use.
Now, the files are saving, and no work being lost since it upon exit, but it is a bit concerning to get a fatal error this often.