I played this game recently and managed to get to 19 moons before it crashed. Here's what happened:
I had just taken my four warriors out on patrol as usual, nothing out of the blue happened at that time, but it was after. I returned to the clan and went to proceed to the next moon, but it came up with an error message (one that i cannot remember). I closed the error message and the game closed. I'm not quite sure what happened, but i was playing in the latest August 10th Windows release. It didn't seem to let me get to 20 moons. I did luckily save right before it happened though, so please fix this bug.
Thank you.