You can't import (.olm) files from Outlook for Mac to Outlook for Windows
Original KB number: 2649169
Summary
Consider the following scenario:
You try to transfer data from Outlook 2016 for Mac or Outlook for Mac 2011, such as email and contacts, to Outlook for Windows. To do this, you try to import the .olm file that was exported from Outlook for Mac. However, you receive the following error in Outlook for Windows:
The file <path>.olm is not an Outlook data file (.pst).
More information
Microsoft Outlook for Windows doesn't support .olm data files. However, there are several methods that you can use to transfer data from Outlook for Mac to a Windows-based Outlook client. These methods require that you use Microsoft Exchange Server.
Synchronize data with Microsoft Exchange Server
If the data is available in a mailbox that is located on an Exchange Server, the Outlook for Windows client can access the data. To do this, the Windows client connects to the Exchange Server by using either Cached Exchange Mode or Online mode.
Export data from Microsoft Exchange to an Outlook data (.pst) file
Use the Export-Mailbox shell cmdlet from Microsoft Exchange PowerShell to export mailbox data to an Outlook data (.pst) file. For more information about the Export-Mailbox shell cmdlet, see:
Note
Currently, Microsoft does not have a utility to convert an .olm file to a .pst file.