I found the problem, I edited a profile to store the game in this directory : /Volumes/Mac_Docs/2frei/Jeux/Minecraft/Profiles/BTW And the game files are correctly stored on this location. But I need to copy my world save to this location each time I quit the game : /Users/2frei/Library/Application S...

I missed the comma too ^^ After correction it works and you're a genius for me But I have an another problem, when I quit a created world, it doesn't appear in my solo world selection. Despite this problem, the world files are still existing in my explorer. Note : I play on OSX 1.8.5 with the last M...