You can easily convert Mac MSG files using MSG File Converter by MacXtra. The tool supports Mac OS Machines.
Start MacXtra MSG Converter on your Mac Computer and choose one option from Add File(s) or Add Folder(s).
Check uploaded MSG file on the software panel and click on the Next button.
Choose saving format from PST, EML, EMLX, MSG, HTML, MHT, CSV, PDF, etc.
You can also select the file naming option and Destination path if required.
Mac MSG conversion process completed successfully, you can see the message of completion.