This is really buggy me. I keep losing all of my contacts (over 400 of them) using 2.1 (happened in 2.0 too). It's obviously a problem with Mobile Me. But I don't know how to fix it. I did resync, replacing all my information on Mobile Me with the information on my Mac. But it's still erasing my contacts (& then later restoring them). And often, when I go into contacts, I get the spinning will in the task bar (on top), indicating that it's downloading (or uploading) something. Anyone have any ideas?