If you have photos on the Cfast card, as recommended above first try to read them with your Cfast card reader and if that doesn't work AND they are important photos then check with the card manufacturer to see if they have recommended recovery software.
When I was primarily using my 1D Mark II I would transfer photos by putting its SD card into a reader. But now that my 1DX Mark II and 1DX are what I use most of the time I transfer images via the Ethernet port. If you are using CF and Cfast cards with a card reader, make sure that you are using very good quality cards from a reputable retailer and be very careful inserting those cards because CF and Cfast socket pins are fragile compared to many other interface systems and easy to bend.
NOTE: there are a lot of lower end Cfast cards that use "CF class" memory and although these fit the Cfast port they only provide CF level performance. Also, memory cards are one of the most counterfeited products in the world and what you often get from large online merchants is a fake which may have both electronic and physical/mechanical deficiencies. After getting some counterfeits from the very large online retailer, I now buy all of my memory cards from B&H and Adorama.
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
