[dnanian]

Yeah, I know -- FileVault makes things especially awkward. Note that if you're backing up a few files, NAV might not cause problems. But it can, because it can determine that perfectly good files are "infected" in some situations, because they match their signatures, and then those files won't copy.

On top of that, it interferes with copying by simply slowing things down incredibly.

So, YMMV. With a Smart Update, you might be able to get away with leaving NAV on. But, if you have trouble, give turning it off a try.

It'll also try to scan the whole FileVault volume, which will definitely be slow-slow-slow.