OLM is the native mailbox format used by Microsoft Outlook for Mac. It can store emails, contacts, calendars, notes, tasks, folders, and attachments in a single archive. The main limitation is compatibility: OLM files are primarily designed for Outlook for Mac, so they cannot be opened directly in Outlook for Windows or many other email clients.
If you need to move an old Mac Outlook archive to another platform, converting the OLM file is usually the practical option. Depending on your destination, you can convert OLM data to formats such as:
- PST for Outlook on Windows
- EML/EMLX for individual email messages
- MBOX for clients that support the format
- MSG for Outlook-compatible individual messages
For larger archives, it is worth using a converter that can preserve the folder structure, attachments, and email properties rather than exporting messages individually.
For this type of migration, GainTools OLM Converter can be used to convert OLM files into commonly supported formats while retaining the mailbox data and folder structure. It is particularly useful when an old OLM archive needs to be accessed on Windows or another email platform. It has a preview option that is also useful for checking the OLM contents before conversion. This makes it
Download and try it from here:OLM Converter Tool - Migrate Files from Mac Outlook OLM into PST, EML, EMLx, MSG, and MBOX