I got a new MacBook Pro last week. Today I had one of those situations where a co-worker claimed not to have received an email I knew I sent a few weeks back. I opened Mail (10.1) and went to look for it just to make sure that I wasn't mistaken. Oddly, it wasn't there, so signed in to gmail on a browser and found it. It's there in the Mail app on my phone and my old Mac too. Why didn't Mail on my new computer download this message? Most of the other messages seem to be there. Is there anything I should do to keep this from happening again?