I’m having a similar issue, I had footage on my Transcend SD card as i checked the footage in my camera before transferring…so i tried to transfer my footage from a card reader onto my hard drive. The transfer crashed and now the card will not open on my computer using a reader. I also put it back into my Panasonic HMC 150 camera and i get a “Check Card’ error message. Is my footage lost or can it still be recovered?