Worlds not loading

No saved worlds are loading. Creative or Survival. After clicking on a saved world, the next screen says "building terrain"... After that the game crashes and it goes back to the Apple TV home screen. Creating new worlds does work. But only for a few hours. Then that new saved game also becomes unusable.

apple tv edition 1.1.5
Sorry. I had to choose a Version from the drop box while creating this issue.