Why do some of my mp3 files not play?
That might be because the file type is unsupported, the file extension is incorrect, or the file is corrupt.” and also the mp3 files in the folder are hidden for some reason.
Which audio format is best for car USB player?
How Car Radios Understand USB File Structure. Unlike a computer, your car radio is very limited in its ability to interpret different USB drive formats and the subsequent file structure. Most systems require that the USB drive be formatted using the FAT or FAT32 file format.