Hi I have a 59 plate S3 with RNS-E headunit fitted. The issue I have is it will not play certain files stored on my SD card. All files are mp3 format but only some of them appear on the list of stored of files on the card. I have tried formatting the card and putting only one file on it which it has previously not recognised. An error message saying unknown files appears and it will not play. I am puzzled because some of the files work and some dont ? Is there a certain type of mp3 file these will not recognise? Any help would be greatly appreciated ! the SD card is a sandisk SDHC 32gb.