USB With Audio Units
When you plug in a USB device, the audio unit automatically searches the USB device for playable music files. See the Owner's Manual for more information about navigating USB menus, selecting music, and music file compatibility.
The audio unit organizes the playable music folders and files that appear on the USB device. If there are any music files that are not located in a folder, the audio unit automatically creates a folder titled ROOT, and lists all these playable music files in it. If your customer complains that they cannot find some songs loaded on their USB device, recommend that they check the ROOT folder for the missing music files. If all the music files on the USB are in folders, the ROOT folder does not appear.
When there are music files not located in a folder, the audio unit automatically creates a folder named ROOT (A).