Continuity mistake: When Gibbs comes to Abbie's lab to inquire about the smoke detector and computer, the CPU is disassembled on her lab table with the "hard drive" sitting on a white tray that is positioned in front of the computer cover that has been removed from the CPU. The "hard drive" is white colored. At the cut to a close up of the hard drive it is now black and a completely different piece, the white tray has disappeared and the hard drive is sitting on the CPU cover. When it cuts back to the wide shot the white try has returned and the hard drive is back to the original white.
Continuity mistake: When Tony's dad arrives at the NCIS office for Christmas, he is met at the elevator by Ziva. He is holding a Christmas present (which looks like a bouquet of flowers) with the 'red' end up. As the camera angle changes, he is now holding it 'red' side down.