RDP to Windows7/8 via Microsoft MacOS X Client and getting "Auth" errors when you KNOW the password, Domain/Computer name are correct? Guess what? Likely it's a key STUCK on the physical keyboard at the terminal. Windows RDP clients don't have the issue as they pass cred differently it would seem. I removed the "stack of paper" that was sitting on the keyboard (client workstation through RDP Gateway) and boom...logged in fine. I then reproduced the error. Yep, auth errors when a key is held down. Awesome. Lucky I had my remote tool that shows client pressed keys and mouse movement.