Leica M Instruction Manual page 217

Note:
The following functions cannot be performed and the menu text
appears in dark instead of light gray to indicate this:
– Protecting a picture that is already protected
– Clearing delete protection for a picture that is not protected
3. Confirm your selection with the
other pictures by pressing right and left on the direction pad (30).
SET button. You can still open
Displays after protection /
Clearing delete protection
After completing the process, the original monitor display appears
again, with the corresponding symbol ( ) for protected pictures.
Note:
The display ( ) also appears if a protected picture is called up.
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