If you have an older Windows OS version, and you are looking for the best MBOX To PST converter program that run on older version as well. So here, I would recommend MailsDaddy MBOX To PST converter program that swiftly runs on all Windows versions.

Some of the main features of MailsDaddy software:

Users can add single and multiple MBOX files at once using the add file and folder button.
This application provides preview features that help to check emails in the mail section before conversion.
Multiple MBOX file export options including HTML, MHTML, EML, MSG, RTF, and PST.
This enables complete data integrity during conversion time without any changes in the original file structure.
After conversion of the MBOX file user can import it into Outlook 2019, 2016, 2013, 2011, 2010, and 2007.
This software supports almost every email client like Mozilla Thunderbird, Apple Mail, Entourage, Webmail, Gmail, SeaMonkey, etc.