You can easily convert Mac Outlook OLM files to PST using MacUncle OLM to PST Converter. The tool supports Mac OS Machines.
Start Mac OLM to PST Converter on your Mac Computer and select OLM file using Add File(s) or Add Folder(s).
Check uploaded OLM file on the software panel and click on the Next button.
Choose PST from Select Saving Option.
Split PST Files using the Option and set a location to store the resultant file.
Message of completion as you can see the Image, press OK button to complete the whole process.