OLM file is a MAC Outlook data file that Windows Outlook does not support any item in OLM format. To convert OLM data to Outlook PST format for Windows, we suggest the MailsDaddy OLM converter tool. This OLM to PST Converter software keeps each data item and provides hassle-free conversion from OLM to PST. You can also use the software to export OLM to MBOX, OLM to Office 365, and various other mail formats.
The software automatically manages the folder structure and provides 100% secure migration from OLM to PST format. If you try the free demo version of the software first then it converts 20 items from each folder. For more detail visit the official site.