WombatSlayer,

that sounds really weird. I don't think anyone else has two versions running to log in. Never heard of. What I think is going on is that the fakeserver lags a bit in its reaction. It's an old problem.

Try this:
- Check "Use existing internet connection"
- Click "Log in"
- Don't wait but click the "Back" (the dog-ear) button to abort immediately.
- Click "Log In" again.