Microsoft Word
 

After reading some Word documents when I close them I am asked if I want to save changes to the document. This happens even though I have not made any changes. This does not happen with all documents, just a few!
Does anybody know why this is happening? What have I done wrong to be asked this question when no changes have been made and how do I fix it?
It's just annoying me!
I am using Windows XP Home SP2 & Office XP.
CC

Could be due to having autocalculated fields in the document, such as Date, this will change on document open, thus the document would need saving.

ZH

Could be due to your having a different printer installed than the person who wrote the document. It'll reformat for the different print metrics and want to save the result.

Going back a few versions, putting "page n of m" in the header or footer could do this - it counted how many pages there were in the document on opening it, replaced all the instances of "m" with the same number, and regarded this as a change that needed saving. I don't know whether or not they've now fixed this.