I recently purchased the newest MacBook Pro & all my software is up to date. I did not use Time Machine from my previous Mac & just added my music/photos from hard drive. I open up the Mail App and have the option to pick account (iCloud, Yahoo, Google, AOL, etc.). I pick AOL and put in my email address & password and click "Set Up". It then asks me to select the apps to use with my email. My choices are Mail, Messages, and Notes. I only check mail. I click Done and nothing happens. It only shows Inbox & Sent. It does not load in my folders, emails, etc. If I try to send an email, I get the error "This message could not be sent because your account does not have a preferred outgoing mail server. Select an outgoing mail server from the list below." If I click Quit under the mail tab, it will not quit. If I try to restart my computer, it will say "The Application Mail canceled restart." To Try restarting again, quit Mail & click Try Again". I have left it open to say if it takes some time to load & no luck.