The current scene I am working on in Bryce 6 just crashed, nothing new of course, lol, but on this occasion, instead of just allowing Bryce to close, I tried moving the crash screen out of the way and going to file and "save as"..and it worked, I didn't lose the scene and all the work I had done was saved!
I don't suppose this always works, but it may be worth a try next time you have a crash!