Was about to say the same thing, when my main project just went belly up for some unknown reason! Otherwise I have to agree, this is the first time it’s happened here since I started using the engine back in april.
Implemented some interface functions in my vehicle blueprint, compiled, saved, tested - everything in perfect working order. Closed the project, had a cup of tea, then went back to continue working, and the darn thing would just crash instantly when I tried to open the project again.
Luckily, I live as I learn, so it’s just a matter of rolling back to revision 106 and redo those functions. Up and running again in a matter of seconds, having lost just about one hour’s worth of work. That really should be zero!
But then again, it could have been months lost instead, without proper security measures.
Now I’ll have to see if this weirdness can be reproduced somehow…