I just tried to email my daughter but the message went to someone I've never heard of. I typed the first two letters into the address line of Mail and thought it filled my daughter's address. When I sent the message I thought I saw out of the corner of my eye that two messages went out so I checked. Apparently only one message went and it was to this mystery person. I Googled the name -she has a facebook page (I don't). The Finder found no reference to her on my computer other than the email and the google search. I'm a little worried that I'm now compromised in some way. Any thought on what happened would really be appreciated? Thanks

Check your Window > Previous Recipients to see if it is listed there.

Yes she's listed there now. Never looked at this list before. Is this a list of all those addresses I've sent email to?

And received from, I believe. It's addresses that are not listed as Junk. You can delete them individually.

Thank you for you interest.
so, do you think somebody using my mail account has communicated with her sometime in the past and I forgot (neither of my kids knows her)?

It's a possibility. I doubt you've been compromised though.

You can also turn off auto-complete in Mail Prefs > Composing.

OK.

Thanks again. I like the auto complete. I'll just have to be more careful in the future.

Yeah, I usually double check the addressee before I hit Send.

No way.