UltraVNC

VNCScan is what we use. It works great, plus you can do a TON of other things with it. And the price is pretty sweet at around $70 for an admin setup.

http://www.bozteck.com/vncscan/pricing.html

Welp, I have figured it out! Turns out it was VNCScan. Though I'm still not sure how it was working on some and not others. VNCScan installed the VNC service as winvnc. Whereas UVNC installs it as uvnc_service. All I had to do was delete the Winvnc service, and install the uvnc service. Once I did ...

No problem, it was worth looking into. I'm afraid there is no UAC event happening when I try to log into the users machine. As mentioned, these are Windows XP machines, so UAC doesn't even exist! We are not using MSLogon, only the built in password.

Agreed on VNCScan, but I don't know if they will ...

I'm afraid I don't follow. What Rudi posted was about initiating a reverse connection. This is just a normal connection. From Viewer to server on a local network. I've also tried setting Debug to 1 and the level to 12 but I'm not getting any log info from it. Help!

We are using UltraVNC 1.9.6.1 deployed via VNCScan. I don't know why, but for the vast majority of our environment it has worked fine. However, recently several of our machines have begun generating a Red UAC prompt. This is very odd as this has only occured on our Windows XP machines. All Windows 7 ...