What I expected to happen was it would open normally and i could mess around with redstone, build stuff, etc.

but what actually happened was it randomly crashed when i tried to play Minecraft on that world.

i have tried using Superflat the first time and it crashed, then i used a program called "MCedit" to make a flat world, and it crashed again.

Steps to Reproduce:
1. make a superflat world or make a flat area with MCedit.
2. try to play on it
3. CRASH...
i think this doesn't happen every time, as i have done both of these before on different world files and it works fine when it starts up, but with this world, it always chrashes. i think this may be a bug with the world generation.