I was having some trouble with OpenVPN (windows) this morning, a confusing error:
TCP/UDP: Socket bind failed on local address [undef]:1194:
Address already in use (WSAEADDRINUSE)
Seems obvious right? I killed OpenVPN, and looked around for other processes, but none were evident. A friend suggested using TCPVIew, which like everything Mark Russinovich writes, is easy to install, super useful, and totally solved the problem almost instantly.
The culprit — PIDGIN, of all things! For some reason, it had port 1194 all to itself! Killing it, restarting OpenVPN worked like a breeze!