After 10.8 upgrade, autocomplete grabs old email addresses

[Kevin L.]

This problem is driving me nuts: I upgraded to Mountain Lion, then set up iCloud to sync my Address Book, Calendar, etc. (just like I had it with Lion) however now when I go to type an email, the autocomplete feature shows me hundreds of email addresses that are NOT in my address book, or my previous contacts. I don't know where it's getting the info from. It suggests addresses of people I contacted only one time, five or six years ago! What's worse, is that it's grabbing them from my home computer's email account and auto-filling my work computer's email (I don't have .mac email accounts, nor do I have Mail synced with iCloud; they're separate email accounts from separate email servers). This never happened under 10.7 Lion.
Does anyone know of a feature in 10.8 or iCloud that now tries to sync autocomplete data across multiple machines? More importantly, is there a way to set it so autocomplete sticks with one computer? Heck, even if I could just get it to only use my Address Book contacts I'd be happier.
Thanks!

[Ccrew]

what mail client?

[Kevin L.]

Sorry... I'm talking about Apple's Mail app.