Canon EOS 6D Basic Manual page 29

Installing and Removing the Card
When the access lamp is lit or blinking, it indicates that images are
being written to or read by the card, being erased, or data is being
transferred. Do not open the card slot cover during this time. Also,
never do any of the following while the access lamp is lit or
blinking. Otherwise, it can damage the image data, card, or camera.
• Removing the card.
• Removing the battery.
• Shaking or banging the camera around.
If the card already contains recorded images, the image number may not
start from 0001.
If a card-related error message is displayed on the LCD monitor, remove
and reinsert the card. If the error persists, use a different card.
If you can transfer all the images on the card to a computer, transfer all
the images and then format the card with the camera (p.49). The card
may then return to normal.
Do not touch the card's contacts with your fingers or metal objects.
29