I use Lightroom 4.2 and my D7000. Windows 7 64bit. Found same issues but realized that once the software did not "see" the camera for live view I restarted the software, plugged in the camera to the computer, started tethered, then turned on camera and waited 20+ seconds for the program to recognize the camera. I also found that turning off the tethered mode in the program forced me to reload he program. Turned the camera on and off for 50+ shots and along as the tether mode was still on Lightroom had no problems seeing the camera.....weird but true.