Canon EOS-1D X Mark III Advanced User's Manual page 806

3.
Select [OK].
(1) Target card
The camera settings are saved to the card.
To rename the file to an 8-character name of your choice before saving
it, press the <
For instructions, see
Caution
Camera settings files saved by a camera other than an EOS-1D X Mark III cannot
be loaded on this camera.
It may not be possible to load camera settings files that were saved by a camera
with a different firmware version.
Note
Up to ten camera settings files can be saved on a card. If a card already has ten
camera settings files, either overwrite existing files or use a different card.
> button on the screen in step 3.
File Naming. The steps are the same.
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