I have a problem with my 1D mark3, it refuses to format the CF cards and comes up with the message "cannot format change card 1" I am also have a lot of trouble downloading and editing the photos. I have tried multiple CF cards with the same result. I have checked to see if the pins that go into the card when mounted in the camera are OK but there is no damage and the cards mount smoothly and with no problems. I have downloaded the latest firmware and that has loaded nicely without any hassles. Aside from having the camera service, do anyone have any suggestions.
I also have a 1d MkIII and tried to replicate your problem...mine works fine everytime. I tried cf cards, sd cards both singly and together and its all fine. Sorry I can't help you. I can help by searching the net for a similar problem...best I can do for now.
thanks for that I shall give it a try, The CF cards are not new, this could be adding to the problem also.
I tried what you said and no luck, the SD card formats nicely, I tried some other cards which all work fine in my 10D but no luck with the 1D. I will try a new CF card next time and see if my other cards have developed a problem that shows up in the 1D.
Sorry to hear that, all the other posts leads to a bent pin in the CF card slot, that would be an ouch and a trip to the Canon repair shop.