I suggest the MacSonik Mac Email Migrator tool that allows you to migrate emails from many webmail clients to other webmail clients  Users can Exports Gmail, Yahoo, Hotmail, Office 365, AOL, Live Exchange, and IMAP to these clients and OST, PST, MBOX, EML, EMLX, MSG, and OLM files. It is simple to convert MBOX, PST, OST, MSG, OLM, EML, EMLX, MSG, PDF, GIF, TIFF, DOC, and DOCX then also you can migrate them from these files formats to MBOX, PST, OST, MSG, OLM, EML, EMLX, MSG, PDF, GIF, TIFF, DOC, and DOCX file formats on a Mac machine.