Matt, you were onto something. I ran BiaB as Admin, ran the update utility, shut down BiaB, then booted it again, as Admin. No popup. So I exited BiaB again, then booted it again normally -- that is, not as Admin. No popup. Yay!

So it appears fixed. I knew I could count on you guys to come up with a fix!

So I gotta ask, what is it about running the program as Admin that causes it to work right?