This is happening to a user in a field office, so I haven't seen it firsthand. It is Office XP. She says that pretty much every time she clicks the "Send" button, she gets a message asking if she wants to save the changes -- she says it's the exact same box you get when you close an open e-mail that you are typing, like this:
I checked her Rules, and it is empty. Is there any other reason why this would be happening when she clicks "Send"?