Having exactly the same proplem with a brand new Sandisk MicroSD card for my Sandisk Clip Sport MP3 player.
Downloaded some perfectly legitimit MP3 files from my Apple Imac and then it reads: Sandisk SD card files system error.
Restart the device or format for recovery. Formatting and reinstalling the MP3 files did not help.
Same problem occurred. I am at a loss how to proceed next!
