When playing 15w39c snapshot, there was no problem at all. Some lags here and there, chunks not loading, but the main issue is that after a few minutes of playing, Minecraft force closes. I checked the launcher, and it said "Deleting 15w39c natives or something like that" then "Couldn't delete 15w39c natives".
I tried to play again after restarting my launcher. The same thing happens, game force closes.