OpenVPN GUI window is empty. Why can't I connect to my VPN?

OpenVPN GUI is probably trying to connect to the management interface of an OpenVPN instance which should have already been started.

OpenVPN GUI will first try to start openvpn.exe and then connect to the port shown above. If you look carefully at your Process Monitor output, you would see a Process Create event pointing to openvpn.exe.

Sadly, OpenVPN GUI doesn't (or can't) capture the output of that process. So you're going to want to start it yourself manually. You'll then see what the problem with your configuration file is.