So what is OLM file? A OLM file is a datbase file for outlook on mac operating system. It is designed specifically to be used on outlook for mac operating sytem .Means that it will only open on mac version of outlook not anywhere else.
Why It is Used?
It is used to store data such as contacts, messages, emails, notes, journals, tasks, calendar and other application data.
How to Import OLM File into Windows Outlook?
This file format is only supported by mac operating system it cannot be opened on a windows operating system. To open mac outlook file on windows operating system it needs to be convert to PST file format, which is the supported file format for outlook for windows.
To import mac outlook file into windows outlook first convert mac outlook file to PST file format using a third party tool or else you cant import OLM file .
There are many thire party software out there in the market which can help to convert a mac outlook file to pst file format each one have their own pros and cons.