Serato will create a folder in each drive for which it has found and imported music.
When you add tracks that are located on different drives to the same Crate within Serato, a Crate will be created on each drive that contains those Tracks.
In Serato, add two tracks to a crate called 'MyMusic':
You will find on both C and D drives in your Serato/Subcrates folder the crate: 'MyMusic.crate'
Import both of these into MIXO to make sure all of your tracks are imported.