You cannot open OLM files directly in Outlook, as OLMs are only supported on Mac. You must first convert the OLM file to a format that is compatible with Windows before importing it into Outlook. The best way to do this is to use an OLM-PST conversion tool such as
GainTools OLM to PST Converter. The tool allows users to convert OLM to PST and preserve all content (email, attachments, contacts, calendar entries, etc.) while converting from Mac OS X to Windows. After installing the program on a Windows PC, users can simply add the OLM file and select PST as the output format, and the conversion will be complete. The resulting PST can also be easily imported into Outlook.
