Game keeps crashing upon loading of personal world

Game keeps crashing upon loading of personal world

What I expected to happen was...:
I expected the game to load and I'd be able to play.

What actually happened was...:
The game got to the point of selecting a world to play in, started loading the terrain, and then crashed out.

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. Load game
3. Press play
4. The game loads up until selecting a world
5. Selecting a world, it shows the loading terrain screen
6. Crash.