Missing email address in hotmail


New Email
Hi, I'm trying to search for a friends email address in hotmail, she has a yahoo account and I've always used that address, however over the last few days that email address isn't coming up when I search for her but instead her old company email address which I'm certain I've not used for a very long time? Why would this address be showing and not her yahoo one? I'm very confused....... I have asked her but I don't understand why hotmail is reverting to this address? Does Hotmail automatically list the last email address you used for that person? Which I'm guessing I could have done by mistake if it came up before and I hadn't noticed.