◪1. USB playing songs must be placed with the directory, you can not have a folder, just put MP3 format songs files.
◪2. USB format is EXFAT.
◪3. USB doesn’t display when open the shutdown, please check if the MP3 chip program without reset.
◪4. USB interface is in bad connection.
◪5. They do not support mixed USB please use brands ,such as Samsung, Kingston, SanDisk, etc.