Minecraft wiki entry for Migrating_saved_game_data_to_the_cloud, associated text: This guide assumes that you only want one integrated Minecraft save directory. If you wish to have separate directories (e.g., for other machines: Minecraft/Linux, Minecraft/Windows, Minecraft/Toaster, etc.), then you should create them on Dropbox and change the instructions here as needed. This guide also will only sync your saved game files, not any .jar customizations (such as mods) or texture packs. If you don't know what those are, then you're probably safe. Note also that you should be careful only to play on one machine (as server) at a time using the shared save folder, otherwise you risk corrupting your saved worlds. (This warning is applicable if, for example, you and your friend share a save directory from different machines. It is unlikely to be a problem if you are only using the machines yourself.)