I think I must be doing something wrong. I can't get the USB audio to work. It always says "unsupported".
I can burn the exact same music files/folders to a CD (as files, not music tracks) and it plays them fine.
For those who are using the USB audio option with a USB memory stick - did you do anything special? What filesystem format is your driver formatted with (mine is FAT32). I have tried two usb drives: one that is 1 GB and one that is 16 GB, both have the same issue.
I only have 8 folders and 247 files on the drives - all mp3 format.