Nikon D750 DSLR Camera (Body Only) - Manual (Page 202)

174
A
Saving Custom Picture Controls
Up to 99 custom Picture Controls can be stored on the memory card at
any one time. The memory card can only be used to store user-created
custom Picture Controls. The preset Picture Controls supplied with the
camera (
0 165) can not be copied to the memory card, renamed, or
deleted.
The options in the Manage Picture Control menu apply only to the
memory card in Slot 1. Custom Picture Controls can not be deleted
from or copied to or from the card in Slot 2.