Snapshot 14w32a corrupt my other versions

Put the summary of the bug you're having here

What I expected to happen was...:
i don't know have happend

What actually happened was...:
after experiencing a snapshot 14w32a I was playing the other versions and just when I open a world or go into a server, my game back to the launcher with the error message.

Steps to Reproduce:
1. launch the snapshot 14w32a
2. create a world and play for few minutes and close the game
3. other versions are corrupted