My music directory is about 18gb with subdirectories for each album. After copying the music directory across to the sd card I can check the files and as I go through the albums some are complete with all the files, some show a list of tracks with 0byte size and some say no files. I have tried an integral 256gb card but it shows as 268gb, I would expect 245-250gb it also shows a serial number 0000/0000. This was after formatting it with the zf5z.