Have been changing some things with my e-mail today after setting up an iCloud account. Not sure if that is part of the problem, but now when I try to access most of my messages in my Verizon.net account, I get a forever-spinning pinwheel and "Loading..." displayed. If I access the Verizon mail on their web portal, everything works fine. I can also access the same messages on my iPhone (iOS 6) fine. Now I have sent a few quick test message from the iCloud account to the Verizon account just now, and they work properly in Apple Mail. But previously sent messages (especially if they included html) just say "Loading". Connection Doctor says everything is OK with both the POP and SMTP verizon server setup. On the Verizon Web Portal, it shows no messages in the spam folder. I am not using any rules for spam filtering. Apple Mail v6.5, MacOSX 10.8.4. Any ideas? ---------- So I tried re-building mailboxes using the menu command in Apple Mail. That sort of "fixed" it, in that the messages which previously wouldn't load are just gone now. But the same messages still show on my iPhone and the Verizon Web Portal.