I backup my OE Address Book by using the Export function to create a CSV (Comma Separated Values) file, and that appears to work OK.
I checked the c:\windows\application data\microsoft\address book\username.wab, which is dated from when I bought the machine over a year ago and has old data. So therefore, it does not contain my OE Address Book data.
Yet, a colleague of mine uses the same version of OE (4.0) and whenever he changes the address book, that .wab file is updated with the data and an updated date-stamp. He backs up his OE address book simply by copying his .wab file.
What makes his .wab file reflect his OE Address Book and mine not? I'd like to simply copy the .wab as he does, but for me that would backup nothing.