ok so every time i go on it says play off line so i press ok and every thing loads so i try to go on a single player world and it says it is loading then BOOM it crashes

it crashes every time i / you try to get on a single player world and it does not let you be online

What I expected to happen was"
it would just open up

What actually happened was...:
IT CRASHED OK I AM MAD !!!!!!!!!

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...