Hi Stan, I am also very familiar with problem solving. I’m a PhD analytical chemist and I have 25 years of experience solving manufacturing problems from every corner of the globe. The truth is that we both only have indirect data to draw our hypotheses. I will concede that your analysis may very well be correct and may also be more likely. But an internal issue that sheds dust need not be a constant source of dust either – it can also fall off with time. And I agree that one might expect to see other problems if it is mechanical and occurring over a long time, but I also find it strange that a company that is building a camera would assemble them in an unclassified environment. But alas … I’m not an expert in the camera manufacturing industry. From a more philosophical perspective, if I had a dime for every time I led a major project to resolve a manufacturing issue and the actual cause turned out to be a complete surprise to the whole team of resident experts … well then I’d have a big mess of dimes. In fairness though, I usually only get involved in projects when the local team is not making fast enough progress toward resolving a critical problem. So the sampling is a bit skewed. So if I were to trouble shoot this dust issue I would start with opening up a new D600 that is showing the early dust problem in a class 100 clean room and do a thorough visual examination looking for parts that show evidence of wear or scrapings. I would also collect the dust particles and analyze them – first by visual microscopy, then micro FTIR and finally use energy dispersive electron scanning techniques if appropriate. I would then compare the dust composition to that of the cameras internal parts. I would also try to visit the location where the cameras are being assembled and/or the sub-assemblies are being made to see if those environments are conducive to the dust I find on the sensor. Of course neither of us will actually pursue such an investigation for obvious reasons. And I have doubt that Nikon (nor any such company) would open their doors to such an investigation (I know my company wouldn’t). So this brings me back to my original conclusion … which is neither of us has sufficient data to say we definitively know the source of the problem and this leaves me exactly where I started. As I continue to study the differences between the D800 and D600, however, I think I’m leaning more heavily toward purchasing the D800 because of the better focusing capabilities - so the D600 dust issue may be a moot point for me. I primarily do two types of photography for my hobby income – high school sports and senior portraits. I frequently make larger prints (ranging from 11x14 to 16x20) from high school sporting events. So the 36 mega pixels would also allow greater flexibility for cropping to get in real close while still making larger prints (albeit 24 MP would also work better than the 16Mp on the D7000). While I do like the higher frame rate of the D600, having more photos with several of them being out of focus doesn’t help. I also understand that I can shoot in DX mode with the D800 to get up to 6 FPS on the D800 if I think this is really critical during a particular sporting event – and I still get the better focusing capability over my D7000. Of course the D4 seems like the best solution … but my annual photo sales are typically less than 10K per year so it’s hard to put 6K into a camera body. Not buying a D4 would also allow me to save more quickly for my next major insane NAS purchase – the Nikon 200-400mm F/4 zoom lens. Cheers!