When saving game it freezes up and crashes

Put the summary of the bug you're having here

What I expected to happen was...:
For the game to return to menu

What actually happened was...:
The client froze and was in no way responding

Steps to Reproduce:
1. Create a new customized world
2. Mess around in it for a few
3. Go to the pause menu and click "Save and quit to title"

Please note that the game doesn't necessarily crash but more along the lines of just freeze up and not respond.