I had a go-round with the Microsoft forums and no one could figure out what the problem was, so I'm hoping someone here can.
When I save a new version of a file and go to attach it to an email, Windows Explorer doesn't show it and so I can't attach it. I can get around this by saving it to the desktop. Then it appears in the dialog box and I can attach it. But it's ridiculous to have to do that. This only happens with files saved today. I tried changing the sort order but they still don't appear in the list.
On the MS support site I found something called Fixit, which actually fixed this problem initially. But now it's back again and Fixit no longer helps. It tells me it finds nothing wrong. Very irritating.