Nikon Z 9 Reference Manual page 782

D
Restoring Default Settings
•
Depending on current settings, some menu items and other features may
be unavailable. To access menu items that are grayed out or features that
are otherwise unavailable, try restoring default settings using the [Reset all
settings] item in the setup menu.
•
Note, however, that wireless network profiles, copyright information, and
other user-generated entries will also be reset. Once reset, settings cannot
be restored.
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