Today when I plugged my new Lumia 920 into my Windows 8 desktop, noting happened. Odd, it had worked the day before.
I unplugged and retried a couple of times, to no avail. Checking Windows’ Devices and Printers showed it was Offline, so I wasn’t imagining that it was installed and working at one point.
I tried a reboot of the desktop, still nothing. As a last ditch effort, I tried rebooting the phone itself, and voila, it reappeared on the desktop.
No biggie, but I saw a few discussion threads online about the same problem. Hopefully this will help others out.