Locate MBOX Files into Mac OSX Mail: Mac OS is an operating system developed by Apple Inc for Macintosh computer systems. It provides excellent GUI (Graphical User Interface) for users to work on their applications.
MBOX holds a large collection of files of email messages. A message encoded in MBOX format begins with a from_line, continues with series of non from_lines and ends with blank line. Apple mail uses MBOX format to store its files. Apple mail is an email client included with the Apple operating systems like OS X, iOS and watchOS. It allows you to hold list of emails related to your business and others. The mail uses SMTP for sending messages and IMAP for message retrieval. It also works with other mail providers like Yahoo, Gmail, Outlook and others.
The above steps open directory in which the emails are stored. The directory is called mail it contains multiple sub folders in it. POP and IMAP accounts are prefixed with POP- and IMAP- respectively. The account folders contain sub folders such as inbox, sent items and others. Mac OS stores email as .emlx files in special .mbox folders. To find and open them you can use Finder option. The above steps are applicable for the Mac Mail versions 2, 3, 4 and above.
Note: It is possible that user library is not visible to you in that case you first need make the library folder visible.