Used my SanDisk Extreme 16GB 120MB/s CF Card once when I took it to Australia Zoo a few weeks ago it went in the camera and I got it out the next day ok.
Worried about the 36GB SanDisk SD card falling apart like my other two so yesterday I put the CF back in the Camera to format it and I could not shut the door so I left it, had another go later same thing.
This morning I tried again the door shut ok this time but I get a Error 2 message telling me to format the card and the camera wont let me do that.
I ring Canon did I get much Help NO after taking my phone Number and email address was told by that person he would email me right back with info on how to send it back to Canon.
Six hours later I was still waiting.
Rang Photo Continental where I bought the camera, spoke to a lovely young man who gave me so much help
Tried out different things and different CF Cards with no success then the door would not close again so he told me to get a torch and magnifying glass and have a look at the pins.
I told him that was the first thing I did yesterday and none looked bent to me, and they still dont look bent, I am taking it back there next week they are going to look as my eyesight is not 100% anymore.
And if needing repairs they will send it to Canon for me. I have found here and on line where the older 7D was having the same problem with CF cards. Not having much luck with new cameras in the past 12 months.