PST to MBOX Converter Software
If you want to convert the PST files to MBOX files, there is a fantastic software called PST to MBOX Converter that can convert PST files to MBOX files in a few simple steps. PST to MBOX Converter is a quick and easy-to-use tool for converting PST files to MBOX files. All of the data can be translated to MS Outlook PST to MBOX format, and the email formatting and other information will be maintained.
Try this software free trial version from here: https://www.emailsoftwares.com/pst-to-mbox-converter.html
For fast and secure migration PST to MBOX, you should use the SYSessential Import PST to MBOX Tool. This tool migrates PST to MBOX as well as provides the ability to convert PST files to various formats (MSG, EMLX, PDF, and Office 365). It removes all errors and never loses single information during the migration from PST to MBOX. This application works well on all versions of Outlook and Windows operating systems. You can check here this tool free trial version:
As an Outlook expert, I recommend you to use Outlook Converter Software to convert Outlook PST files into different file formats such as EML, MBOX, OST, EMLX, HTML, PDF, etc. This tool also migrates your different Outlook data files (.pst) to various email clients like Gmail, Yahoo Mail, Office 365, IMAP, etc. You can use this tool as per your needs.