I've found that this is most often due to people putting the amount of student up past 150. If you bring it down, it won't crash anymore.
the game has a system where it juggles all the students, putting them in places, giving them relationships, personalities, schedules, and the like.
So imagine having the game randomize and and keep track of all those people. It crashes cause it's too much for your device. I would suggest testing it with fewer students, until it doesn't crash.
(Mine stopped crashing at 56)