My worlds keep deleting after when I'm saving and exiting. It's happened six times. The first two times I didn't have back-ups, but the rest of the time I did. Except it keeps happening within hours of each other and I keep losing progress on all my worlds. I would almost have to create back-ups every hour just to not loose progress. I've lost two worlds completely and four I've lost hours of progress. It always happens between saving and exiting, like it doesn't finish saving before it exits. Both creative and survival worlds were lost.