having the exact same issue http://teamviewerforums.com/index.php?topic=2173.0
any luck fixing it?
could you share some of the things you said you found but didnt work for you, wouldn't mind giving them a go to see if helps fixes mine.
thanks
I read an article posted by someone who was using a Mac Mini and was having the same issue as you. They would get a black screen when no monitor was plugged in via HDMI, but once a monitor was plugged in it would work. They eventually found an adapter that was a ThunderPort (?) to VGA adapter and once that was plugged in, it would work even if no monitor was connected to the adapter.
Another post said that they disabled their screensaver and it fixed their problem.
My machine doesn't have a screensaver set and it isn't a Mac Mini and I haven't tried connecting a monitor since all I have in onboard video via VGA port and I do not have a VGA monitor to test it with right now...
Also, I submitted a ticket the same time I posted this thread and it's been acknowledged as received but I haven't heard anything back yet.
In the mean time, I've setup my Windows Home Server 2011 as a VPN and fixed all the port forwarding, etc in my router so I have just been VPN'ing into my home network and server and then using Remote Desktop. It's a few more steps, but it is working for me for now. I would still like to get TeamViewer back up and running though...