I had a rattle from my pop up flash, the store I bought it from pulled another D800e from stock, and this rattled even more. When I used video on the camera you could here the rattle, so it bothered me. So I investigated. I removed the screw holding the sliding arm from one side of the flash,and examined the arm. Then I figured that a little bit of delicate bending of the arm may take up the play, which appeared to be the back end of the arm on a mushroom piece of metal fixed to the flash arm. After the tiniest of bending with very small watch makers pliers, I reassembled it. Hey presto, not a sound, I didn't even need to bend the other sliding arm. So one arm had far more tolerance than the other it seems. Tried the flash over 28 shots and there's no bind, best of all, no rattle! Now I'm happy, shouldn't have had to do it on a £2500 electronic item, but well worth it. Just be wary if you plan to do it yourself, I've spent many years delving into and repairing electronics with the Army, so this didn't phase me, but it's not for the feint hearted.