1.7.10 Crash when building terrain

Put the summary of the bug you're having here
After selecting world and selecting to open

What I expected to happen was...:
World to open where I left off

What actually happened was...:
Splash screen has "building terrain"

Steps to Reproduce:
1. Create profile to use 1.7.10
2. Create world with large bio in creative, cheats on
3. Load 2nd time