LR4.2 (running under Win7 - 64bit) does not see either my D800 or D700 for tethering - says "No Camera Detected" or something similar. It will import pictures directly from both cameras. I tried different cables, USB ports, reboot, different sequence of connections and turn on tether mode, power camera on etc to no avail. Waited as long a 3 minutes (as suggested by one web posting that indicated it took as long as two minutes for LR4.2 to recognize the camera on a Mac) still no fix.
I still have LR3.6, and it recognizes the D700 for tethering, but not the D800 since that is not supported in that version.
My searches last couple of days mostly just led to "LR4.2 now supports D800" without any mention of how to fix the problem of "No Camera Detected" in LR4.2.
I tested Lightroom 4.2 in Windows 7 x64 with D700 and it works fine. I can remote trigger from the PC and tether capture. Re-install Lightroom might help.
