1. Small osu! installation on your programms directory
2. Easy backup your songs and / or replays since it could be a own partition on your harddrive
3. Move your songs everytime you want, osu! don´t take care about it
4. Additions to osu! take no care about it and should work fine
5. ...

1. Win7 or higher
2. Not testet if some additional programms throw errors, but it should be fine

SPOILER

I moved the directories

1. "Exports" (With a lot own mapped maps it could be big)
2. "Replays" (Because i export nearly all and dont want to grow up my system partition for this)
3. "Screenshots" (Could be big with the time - maybe move it at your pictures folder on system?)
4. "Skins" (Could be big too)
5. "Downloads" (Dont know if it could very big while downloading a lot, but dont use system partition if it not required)
6. "Songs" (Will be big!)

1. Move Your directorys from osu! to your destination location (osu! should be closed)
2. Press Windows-Key
3. Type cmd
4. Rightclick it and start as administrator
5. Go to your osu directory with the console (See at "How to navigate with console")
6. Type the following command for each moved directory: (Example for Songs directory)
   

   mklink Songs D:\Songs /D

   So it is "mklink" (the command), the osu! directory you need to link (here "Songs") and the new destination (absolute path). The parameter /D is for directories, if this parameter missed it dont work!
7. Finnished - Play osu! as before

1. dir list all files and directories in current directory
2. drive: change your harddrive, so "c:" switch to C, "d:" switch to D: on your drives. Dont forget the ":" here
3. cd .. Go to directory above
4. cd dirname go to named directory (if it contains spaces, you have to pack it into ", e.g. "Programm Files")
5. exit close console

SPOILER

Zallius wrote:

I don't see the point. You can install osu! anywhere you like and splitting the location of game files just complicates things.

MillhioreF wrote:

You can already specify a custom songs folder location in the .cfg if you really want. None of the other folders are so big that copying them should be a huge burden on disk space (unless you have a billion skins...)

Alternatively, osu! can just be moved into another drive.

I don't see the point. You can install osu! anywhere you like and splitting the location of game files just complicates things.

None of the other folders are so big that copying them should be a huge burden on disk space (unless you have a billion skins...)