You can follow these steps to find out MBOX files generated by Mac Mail application. For Mac Mail 2, 3, 4 and Above Editions. Run the Finder Window and go to Home directory.Use Home button from toolbar menu to read the Home directory.Go to Library Mail and find the mailboxes i.e. Inbox, Drafts, Sent Items, etc. in MBOX format. For Mac Mail 1 Edition. Run the Finder Windows.Select Go from the Menu bar and Go to Folder from the menu. Type ~/Library/Mail/V(x), where x is the version of Mail you have. V2, V3, V4, or V5. Now press Ok button.Mac Mail email client stores the mailboxes in the subfolders of Mail directory.