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5D Mark iii Card2 cannot be accessed problem


I'm getting a faulty error message in my 5D Mark iii


"Card2 cannot be accessed

Cannot auto switch rec. card"


This comes after the camera is switched on, after about 12 seconds of top display coming on, but the rear display screen remaining blank. Only after the 12 seconds does the camera make the sound  it always does when it turns on.


When the CF card is removed and the camera is turned on with only the SD card in the Card2, the error message reads:


"Card2 cannot be accessed

Reinsert/change the card or format card with camera."


I've tried formatting all my SD cards and reinserting them, doesn't work. It doesn't seem to matter which card is used in the SD card2 slot. The problem happens with both SD cards and MicroSD cards in scan disk micro sd adapter.


From what I can tell, this is a problem with the camera/card2 slot, not with the cards themselves.


Does anyone have suggestions or solutions?


Please help!



Can you shine a light into Slot 2 and see if perhaps some dust or something is in there?


You can also get a slot cleaner from Amazon. It is called ClearConnections. It has worked on two cameras that were showing card reading problems.

John Hoffman
Conway, NH

1D X Mark III, Many lenses, Pixma PRO-100, MX472, LR Classic


"Does anyone have suggestions or solutions?"


The suggestion and solution is simple, call Canon 1 (800) 652-2666.  

EOS 1DX and 1D Mk IV and several lenses!