Quit and Reopen Apple Mail to Receive Messages
Apple (via Mac Rumors):
For some email providers, new email messages in Mail may only appear to arrive when Mail is first opened. No new email arrives until Mail is quit and reopened.
What’s odd about the continuing Apple Mail problems with Mavericks is that Mail used to be a very reliable app. I’m not sure why the internals were reworked so extensively in 10.9, since there are few outward changes, but the result has been bugs and slowness.
Update (2014-02-18): Dr. Drang:
So I’m using a mail client that can’t be trusted to send or receive mail. Can it get worse? Yes. I learned this past week that searching doesn’t work, either. Or at least not consistently.
[…]
That, in fact, is the most annoying thing about this mess. Apple has broken the covenant. The deal was that I get a mail client that isn’t fancy but works, and in return I don’t complain about a lack of features I’ll never use. It’s a simple arrangement that’s worked for nine years, and now it’s all this.