Nikon D810 - Manual (Page 274)

250
In full-frame, zoom, and thumbnail playback, press the
L (Z/Q) button to protect the current picture from accidental
deletion. Protected files are marked with a P icon and can not
be deleted using the O (Q) button or the Delete option in the
playback menu. Note that protected images will be deleted
when the memory card is formatted (0 366). To remove
protection from a picture so that it can be deleted, display or
highlight it and press the L (Z/Q) button.
Protecting Photographs from Deletion
L
(Z/Q) button
A
Removing Protection from All Images
To remove protection from all images in the folder or folders currently
selected in the Playback folder menu, press the L (Z/Q) and O (Q)
buttons together for about two seconds during playback.