#16. "RE: D800 images can't be used with just upgraded LR 4" In response to In response to 0
I had troubles with LR3 not opening the D800 RAW files and found that Adobe had an upgrade to the Camera Raw plugin. When I downloaded it, it was a beta one but once installed, it was happy to open the D800 sample files I wanted to look at in both Photoshop and LR.
Maybe the difference is 64 bit v's 32 bit Windows for those who can't get it to work. My upgrade to LR4 is still in the mail.