There are lots of options available for the conversion of OLM to PST on the Windows but there is a penalty of solutions for the Mac OS. I recommend a software named Mac OLM to PST Converter which is a Mac-based utility and transfers the data from OLM file format to Outlook PST file format. To check how this tool works you can try its trial version. Visit:- toolscrunch.com/mac-olm-to-pst-converter.html