Two out of these three cards have failed. Thankfully none happened at times when I absolutely just didn’t have the shot because of the failure. After doing a search, it seems these cards are from a bad batch. They are being RMA’d to SanDisk. I’ve got other cards, so this is kind of an inconvenience but won’t lead to any down time. If you have recently purchased 8GB Extreme IV cards from Adorama, check to make sure they are not in the batch BI090506477B. If you have some that are, take pictures until you fill the card up… if you can. Seems to fail when the card is half full.