You can easily convert Mac MBOX files using MBOX Converter by MacXtra. The tool supports Mac OS Machines.
Start MBOX Converter on your Mac Computer.
Select MBOX file using Add File(s) or Add Folder(s).
Choose saving format from PST, EML, EMLX, MSG, HTML, MHT, CSV, PDF, etc.
You can also select the File Naming Option and Choose Destination path if required.
Mac MBOX conversion process completed successfully, you can see the message of completion.