About the Mac Mail Client

Mail.app (also known as Mac Mail or Apple Mail or simply “Mail”) is the email program included with the Mac OS X operating system. 

The Mail.app mail storage format has changed since the initial version 1 release.  When acquiring the donated email, it will be helpful to find out what version of Mail the donor was using.

Mail version 1
(Mac OS X v10.0 "Cheetah" released 24 March 2001 thru Mac OS X v10.3 “Panther”, released 24 October 2003)

In Mail version 1, the mail storage format is an mbox bundle (a folder for the mailbox (e.g., “inbox.mbox”) that contains a single mbox text file containing all messages in that mailbox.  Attachments are encoded with the message inside the mbox file.

Table 1: What to look for in Mac Mail version 1

Mail version 2 (Mac OS X 10.4 “Tiger”, released 20 April 2005)
Mail version 3 (Mac OS X v10.5 “Leopard”, released 26 October 2007)
Mail version 4 (Mac OS X v10.6 “Snow Leopard”, released 28 August 2009)

Starting with Mail version 2, messages are stored individually in .emlx text files that are bundled inside a “Messages” folder inside a [mailbox_name].mbox folder.  Each individual emlx message file is named with an incrementing number:

~/Library/Mail/Mailboxes/inbox.mbox/Messages/
                                                                           5521.emlx
                                                                           5522.emlx
                                                                           5523.emlx
                                                                           …

Attachments are encoded with the message inside the emlx file.

Table 2: What to look for in Mac Mail versions 2+