Have a Look at the Features of PST to MBOX Conveter
Convert PST File to MBOX
This application converts Outlook emails and other indispensable Outlook items into the MBOX file format. Moreover, it creates a single MBOX file for each Outlook PST file and moves PST data (emails, contacts, calendars, attachments, notes, tasks, etc.) to it.
Keeps up the Maintain Folder Hierarchy
It does not make changes in the hierarchy of folders/sub-folders and even keep it intact from being any kind of deterioration. This is sort of an advance option which is used to maintain the original folder structure of PST file.
Preview Outlook PST Items
When utility initiates its processing, then it starts rendering a count details about the conversion on the screen. This count details includes current folder, folder count and numbers of emails that were passed under this conversion.
Get Retained Data
PST to MBOX converter gives a promising result and that is keeping data integrity same as it was. If you have lately exported Outlook emails to MBOX, then converted data will be retained with major meta attributes such as CC, To, BCC, etc.
Tools generate an MBOX file at the end of execution, which can be accessed on various platforms such as Apple Mail, Thunderbird, Eduora, etc.