I recommend PST to MBOX Converter Software, that I have personally used in the last few months and that can easily export or convert the Outlook PST file to Thunderbird MBOX file format in just a few clicks. The utility’s advanced options make the conversion process quick and seamless. This tool is compatible with all current versions of Windows and Outlook. This software’s free trial edition is available to users.
Use CubexSoft PST to MBOX Converter software that will help you to convert multiple Outlook emails to MBOX file format with all emails, formatting, meta header, and other items along with attachments. This software supports all MBOX-supported email clients like Thunderbird, Apple Mail, Eudora, SeaMonkey, etc.
Hi, you can use the alternative reliable DRS Outlook PST file converter tool which is capable to save PST files in EML, MSG, MBOX, HTML, Gmail, Yahoo, AOL, etc. The free version of the utility is also available to evaluate the performance of the tool.