Indeed I can see the Directory in the page showing that the the USB is connected but clicking on the directory name shows blanks. Most peculiar that the directory name is visible but the files cannot be located ! I'll try and see if the add to an existing playlist will work.
When the keyboard shows files, it shows only files of the type you ask for. If you press the registration icon first, it will list only registrations. If you press the Style icon first, it shows only styles. In other words, it operates the same way as the Tyros.
So you must press the Song icon first (either A or B). Then it will list midi files in any of your folders.
Fred