John, I'm assuming you are following the thread directly below. If the timing on your problem was roughly a week ago, you may be running into the same thing. Some of the resources listed below talk about programs locking up during save operations etc.

We have a computer at work that no longer will drop down lists in custom Outlook forms. I'm involved because I designed the form. The timing is similar so I now think that computer was also affected. I'll look into that on Monday with our IT resource person.