I've had the card for a couple months it formatted in my tablet and I could write to it but it screwed up the sleep button, every time the screen went black the tablet turned off, when i replaced it with a 32gb card everything went back to working fine. Tried putting the 64 gb card in my Galaxy SIII, it formats and the phone recognizes the memory but I can write anything to it, it starts but then slows down and stops before it finishes. I can't format the card with windows 7 at all. The card is useless, i'm contacting SanDisk now to see if it's a problem with the batch but I'm probably just screwed.