I had the same problem with my Nikon d800. It was a green and yellow horizontal line going across every picture.
It was very faint and hard to see, but it was there and in a very crucial part of my photos.
I'm very disappointed with Nikon! Their seems to be so many problems with the d800. I never read anything bad about
Canon cameras! For the money Nikon wants for this camera, it should be flawless.
I ended up replacing the camera from Best buy.
I thought I would be able to upload a pic, but by the looks if it, I take it that I can't on this site!? Weird!<div></div>