I was very excited to buy this card (64 gb) for my Samsung Galaxy Note 2 - The product arrived promptly and I was able to format it to EX Fat and use it right away in my smart phone. However, exactly 10 days later when I removed the card (after turning off the phone) and inserted it in my Desktop, I got an error saying that the card was corrupted and unreadable and that I needed to format it.Since I had already got a lot of data on it, including a lot of videos and images of our new-born twins, formatting was not a viable option.I tried to get the card working on my PC Desktop, Mac Air laptop and the Samsung Galaxy Note, but to no avail.  Finally I decided to format it. There too, I kept getting errors and that the computer was unable to format the card.  Finally I tried "Full Format" via my pc - got an error again and then right away "Quick Format" and that worked - so the card is back and working in my Note again, but now I wont trust it anymore - not after having lost so many irreplaceable images and videos.I am a professional photographer, and use memory cards all the time - this has been the worst of the lot !!