Nikon D810 - Manual (Page 190)

166
A
Measuring Preset Manual White Balance (Live View)
Preset manual white balance can not be measured when Record
movies is selected for Custom Setting g4 (Assign shutter button,
0 364) and the live view selector is rotated to 1. Preset manual white
balance can not be set while an HDR exposure is in progress (0 184) or
when a setting other than None is selected for photo live view display
white balance (monitor hue; 0 43).