01-06-2020 08:59 AM
I'd try re-inserting the card into your gopro. If that fails, make sure it can be read by your computer and back up the files on there as I think you may need to reformat the card.
if its fairly old, i'd consider relegating it to backup duty and getting yourself a new card. Also, make sure its a high speed card as slower cards will not work with gopros (or any digital video recorder for that matter) without significant risk of losing your footage