Put the summary of the bug you're having here

What I expected to happen was...:
I think I will use the seed to creat a new world.

What actually happened was...:

The game freezes and shows "converting world" on the screen.
However it only happens in 1.4.2 while 1.3.2 is ok.
Since other players have same results as well, I think it maybe a bug or glitch.

Steps to Reproduce:
1. Use the seed -7515719090508425842 or QUATREPOINTDEUX
2. The game will freeze and show "converting world"

My English is poor. lol