Get CubexSoft MBOX Converter is also available as a free trial edition that helps both professional and non-professional. The free version export the first 25 MBOX emails to PDF Adobe Reader without any paid. It can export bulk emails from MBOX to PDF file format within a single time process.
Read More: https://www.cubexsoft.com/mbox/

Before Choosing the Best MBOX File Converter you need to verify these things:- Batch conversion, User-friendly interface, Multiple File Format Portable, etc. I recommend WebbyAcad MBOX Converter Tool as the Successor of all these points. You should use it on any Kind of Windows OS like - 7,8.0,10,11. Before taking its Premium Version you should also try the Demo Version in which you get 25 Mail per folder.

Take a Demo Version:- https://www.webbyacad.net/mbox-converter.html