PST and MBOX are two different database files which supports their respective email client, If you wants to convert PST files to MBOX format then you can try most effective and easy to use ZOOK PST to MBOX Converter software. It is dedicated tool to recover and transfer complete mailbox data of Outlook into MBOX file for email clients like Eudora, Mozilla, Thunderbird, Entourage, Netscape, Opera Mail, Apple Mail, etc. It is fully supportable to PST files of all versions of Outlook 2021, 2019, 2016, etc. A free demo version of the software is also available to checked out the features and function of the software.