Problems sometimes happen, and Nikon is learning that the hard way, not that it didn't have faulty devices before.
People who bought a Nikon D4 or D800 camera may have experienced lock-ups.
That is to say the camera suddenly stops responding and only pulling out the batteries allows for a subsequent reboot.
Nikon hasn't found a permanent fix for the problem yet, but it is looking for one. In the meantime, it has described a method of circumvention.
Users need to turn off both the ‘Highlights’ and ‘RGB Histogram’ display options in the ‘Playback Display Options’ sub-menu found in the ‘Playback’ menu.
There is another problem that the D800 might exhibit, namely the LCD being constantly out of focus. The viewfinder alignment is imperfect on some of the cameras shipped and there is no way to fix them yet, even after sending the product in for a repair.