I love the idea of having a portable Minecraft installation. Syncing between machines or even giving your worlds and mod-setup to a friend. Before Minecraft’s updated launcher, the only way to change the data storage location away from “%APPDATA%\Roaming\.minecraft” was to create a .bat script and set the system’s APPDATA variable.
The updated launcher is about a year old now, but the concept of a portable installation might not be familiar to everyone. The whole process is now much less complicated and can be done mostly through the Profile settings. Here’s how it goes.

  1. Visit https://minecraft.net/download and download Minecraft.exe.
  2. Create a folder wherever you’d like your installation to go. It will be simplest if the location can be the same on any computer you go to. Using a top-level domain such as right in the C:\ drive or in Program Files would be great. If you’re doing it on a flash drive for ease of carrying it around, I suggest copying it to a hard drive while playing and back to the flash when done. Minecraft saves constantly and this will wear out a flash drive pretty fast.
  3. Move Minecraft.exe to the new folder.
  4. Now, to keep your top-level installation folder uncluttered, create a folder inside called data. This will be the replacement for the standard “.minecraft” folder.
  5. Launch Minecraft and login.
  6. Click New Profile and in the new window that pops up check the box Game Directory right below Profile Name.
  7. In the Game Directory text box, put the full path to your portable installation. (Go into your data folder and click the address bar on top to be able to copy that full path, otherwise just type it in)mcportable_settings
  8. Click save profile and that’s it!

Minecraft_Launcher_Steelsouls

The key to keeping this working is that Minecraft always knows where you want to save all the data. It will go looking here when trying to load, including your world saves and mods. Just make sure to remember this when transferring to a new computer.
If I’ve over-complicated anything or you have any questions please let me know in the comments!