Please explain how new email accounts work

I add a new email account with cPanel. Its created in two spots.

/home/user/mail/.address\@domain_com
and
/home/user/mail/domain.com/address

WHY? when mail comes in from the internet it goes to the first spot and outlook can see the new messages, but when it gets delivered by a local server right beside this cpanel machine it gets delivered to the second spot and outlook can't see the new message.

Why is this happening?

 

it might be working now, outlook can get the mail. I can't understand the reason for two spots though.