If you're looking for a Free MBOX to OFFICE 365 migration solution, I'd like to suggest eSoftTools MBOX Converter, which is the greatest third-party tool for rapidly converting MBOX to OFFICE 365. MBOX to PST, MSG, EML, EMLX, NSF, HTML, OFFICE 365, GMAIL, and YAHOO are all supported. Bulk MBOX files can also be exported to other file formats. It provides a free trial pack that allows users to export the first 25 MBOX objects to PST or other formats.
For more info:- Free MBOX to OFFICE 365 migration
For more info:- Free MBOX to OFFICE 365 migration