I inserted the card into card reader (as I've done a hundred thousands times before over the years), card reader plugged into macbook. Card doesn't show up. Eject, insert again, same thing. Try again, card shows up. Then disappears. Tried another USB port on computer. Same thing. Ran photo rescue software, it appeared to get back all raf files (as viewed in photo mechanic), but when I try to open in capture one, photoshop or lightroom, got corrupt messages.
did more testing with other cards with same result. All were new cards. All were the same type of cards.
Going to try a UHS 2 card to see if it helps.
Got the camera from Fotocare in NYC. Interestingly the box didn't have an instruction book in it. I'm wondering now if this was some sort of return they received.