system
8
Well, I’ve discovered what the problem was. It’s an incompatibility between avast! and an internet accountability program I use called Covenant Eyes (www.covenanteyes.com). If I log in to Covenant Eyes manually before the update then everything works fine. However if I try to let Covenant Eyes log in automatically, avast! update hangs. So, the reason that everything was working in my second post above was that it had obviously already logged in before I tried the update.
Oh well. I’ve sent an email to technical support at both companies so hopefully a solution will be found!