Connect with us


A Guide to Outlook OLM to PST Conversion

Last updated by


converting OLM to PST for Outlook

Did you know some professions have email retention policies? For example, emails must be kept for a decade in the legal profession!

The IRS requires emails to be retained in public companies and all industries for seven years. Only Government and education have lesser terms of three and five years, respectively.

Managing emails can be challenging, especially with Microsoft Outlook’s 40% market share of email management systems. This is because Outlook supports both Windows and Mac operating systems, which use non-compatible file formats – i.e., OLM for [macOS] and PST for [Windows OS].

Microsoft’s lack of a native solution for transferring files from MacOS Outlook to Windows Outlook requires a file conversion to convert the OLM file to Outlook PST file format so the user can access their Mac Outlook mailbox data in Outlook on a Windows system.

Here is a guide on the options for converting Outlook data, scenarios that may require OLM to PST file conversion, and the benefits of using an OLM to PST converter.

Understanding OLM and PST Files


The OLM (Outlook for Mac) file is used by Microsoft Outlook for Mac to store and archive Outlook features, i.e., emails, contacts, calendar events, tasks, and notes. It transfers data between MacOS installs, for example, an install on an iMac and a Macbook Air laptop.


The PST (Personal Storage Table) file is similar to the OLM insofar as it is used by Microsoft Outlook for Windows. It can also be stored on your computer and used to transfer data between Windows-based Outlook installs.

Scenarios That Need OLM to PST Conversion

So far, we have mentioned migrating Outlook data to a Windows-based computer from a Mac. Corporates often take this action; their IT groups manage the OLM file to PST file conversions so their staff can use their email data with the Windows operating system. Other events that require the OLM to PST conversion include:

  • Backup and archiving – if you wish to create a backup of your Outlook for Mac data that can be easily accessed on Windows systems, converting OLM to PST can be beneficial.
  • File compatibility – you may be given a .olm file, but you cannot access the data if you’re on a Windows-based computer. First, you’ll need to convert it to a PST file.
  • Third-party email clients – if you are using more than one email client and need the data in your Windows Outlook

File Conversion Methods

Two options for converting OLM files to PST files are manual and automated with a third-party converter tool.

1. The manual conversion (indirect method)

The first action is to export to IMAP Account. Set up an IMAP email account and sync your Mac Outlook with this account. After syncing, set up the same IMAP account on Outlook for Windows and download the emails.

Using Gmail’s IMAP protocol

Using Gmail’s IMAP protocol, you must follow several steps to convert an OLM file to a PST file. First, you’ll export your Outlook for Mac data to Gmail using IMAP. Then, you’ll import that data from Gmail into Outlook for Windows.

using gmail IMAP for transfer files

Additionally, you can export individual items, emails, contacts, and calendars to formats imported into Outlook for Windows (e.g., using .ics, .csv, and .eml formats).

Considering the manual method’s easy availability, many users may like to convert OLM to PST for Outlook. However, the manual approach has challenges. For example, it is time-consuming and involves many steps, requiring another email client, like Gmail, to start the process.

Moreover, there is also a risk of data loss if the user accidentally makes any mistake during the manual process. Realistically, the person managing the manual conversion must be technically proficient and skilled, not your everyday computer user.

2. Using OLM to PST converter tools

You must select a reliable converter tool like Stellar Converter or Kernel. Then, install and run the software on your Mac. Add your OLM file and follow the software prompts to convert it to PST format. This is a straightforward and quick process.

Now that you have a PST file, you can import it into Outlook for Windows using:

File > Open & Export > Import/Export > Import from another program or file > Outlook Data File (.pst)

A tool like Stellar Converter provides data protection, security, and the original folder hierarchy post-conversion. It also offers features like selective and batch conversion, preview, a log report, and converting to other formats.

Why Use OLM to PST Converters?

The core benefits of choosing a converter over the manual process include ease of use, time-saving, and data integrity.  The user doesn’t need to be technical to get the job done.

With the third-party converter, you get seamless access to data on different systems, can use the converter tool as a backup and recovery strategy, and get technical support from the converter provider.

Summing Up

Microsoft Outlook holds a significant market share in email management. Mac and Windows users use it, and often, email data needs to be migrated from a Mac to Windows.

The manual method requires an IMAP account, which is doable with a Gmail email account, but the conversion process is lengthy and time-consuming, and there is room for errors.

Using an OLM to PST converter is more reliable and quicker, and non-technical users can do the process.