I made a world in 1.6. I then started playing on the world in the latest development version. I used the /tp command to teleport me to a chunk that was not already loaded. I think it's because of this that the world crashed and I can no longer play on the world.
Steps to Reproduce:
1. Create a world in 1.6.
2. Leave the game and relaunch it in 1.7.
3. Play the world in 1.7.
4. Teleport to a chunk that is not already loaded.