I'm not sure if it's saving over my currently open file. I usually do a lot of experimental changes to my game and see if it works, and if doesn't i'll close it without saving anything. Every time I manage to make something that actually works well, I save a new file.
Construct 2 has been crashing when opening my previous version and i haven't saved any changes to it. I was thinking that if there's been any automatic saves that would have corrupted the file when Construct has been crashing. A file previous from that opens and works well and I have work hard to make the same changes to it.
usually I don't like anything happening "behind my back".