OLM File Extension – What is an .OLM File?

Microsoft Outlook uses data files, such as .OST, .PST and .OLM to store the mailbox data on your local system storage. However, the OLM file is not created by default. Instead, Outlook for Mac creates a .OLK file to store a local synchronized copy of mailbox items, such as emails, contacts, attachments, etc., from the Exchange or email server. However, a user can export the mailbox items from Outlook for Mac to OLM files whenever they want.

OLM File Extension- An Overview

OLM Outlook data file is often used by Outlook for Mac to backup, import, or migrate the OLM files to another system or Outlook for Mac profile. First introduced with Microsoft Outlook 2011, the OLM file is still used by the new Outlook for Mac 2016 and 2019 versions to store mailbox data.

An OLM file can store all kinds of mailbox items, such as email messages, contacts, attachments, calendars, notes, tasks, journals, etc., including the archive data.

OLM File Location

Many users try to search for OLM locations on their Mac systems. However, the OLM file is not created by Outlook for Mac by default, and there’s no default .olm file location. Thus, you can’t find an OLM file unless you have already exported the mailbox items to an OLM file via Outlook for Mac.

However, Outlook for Mac users can export the OLM file to any desired location. It could be any internal storage volume, external media, or network storage.

OLM File Size

Although there’s no maximum limit defined for OLM files, it’s recommended to keep the folder size in Outlook for Mac under the 2GB limit. This is important to ensure optimal performance and avoid problems with Outlook for Mac, such as corruption and data loss.

But the problem is that you cannot find or check the folder size in Outlook for Mac unless you drag and drop the email folder to the Desktop or any other folder location.

Advantages of OLM File

Outlook OLM file format allows macOS users to transfer their emails from one Outlook Mac profile to another. This helps Mac users retain their old emails when they upgrade their macOS machine or Outlook version.

Outlook for Mac users can also backup their emails to OLM files and then import them later to any Outlook profile on Mac.

Disadvantages of OLM File

OLM file has some significant drawbacks that you must know.

First, the OLM file extension is strictly built for macOS or Outlook for Mac. You cannot import the OLM file (unlike PST) to Outlook on Windows. However, you can use third-party OLM to PST converter software, such as Stellar Converter for OLM, to import or migrate email items from OLM files or Outlook for Mac to Outlook on Windows.

Second, when you export an OLM file from Outlook for Mac, the export wizard exports all items, including contacts, from all profiles configured in Outlook for Mac to a single OLM file. It does not give you any control or option to export specific or selected email folders or items from individual profiles to OLM. Also, it does not export empty email folders to OLM files.

Similarly, you can’t select accounts while importing the OLM file in another Mac or Outlook for Mac profile.

Third, the imported OLM file does not sync with the mailbox on the server. Thus, you can access and read emails or items locally, but those items will remain on your local drive only.

How to Create or Export OLM File in Outlook for Mac

To create or export an OLM file, you need to follow slightly different steps in Outlook for Mac 2011 and Outlook for 2016 or 2019. Based on the Outlook for Mac version, you can follow these steps,

Steps to Export OLM File in Outlook for Mac 2011

• In your Mac, open Outlook 2011 and navigate to File > Export…

• In the Export wizard window, select the items you want to export in the OLM file. When you are done with the data selection process, click on the Right arrow to continue.

• Select ‘No, do not delete items’ to keep the exported items in current Outlook for Mac or choose ‘Yes, delete items after they are exported,’ if you want to delete the exported mail items. Click the next arrow to proceed.

• Enter the file name with the OLM file extension and choose the save location. Then click the Save button to continue.

• Outlook for Mac 2011 will start exporting the selected mail items to an OLM file.

After Export completes, you can import the OLM file to a different Outlook profile on another Mac.

Steps to Export OLM file in Outlook for Mac 2016 or 2019

1. Open Outlook for Mac 2016 or 2019, navigate to Tools, and click Export.

• Select the desired mail items you want to export to OLM from the Export to Archive File (.olm) window, and then click Continue.

• Enter the file name with the OLM file extension and choose a save location. Then click ‘Save.’

• Outlook for Mac will start saving the selected mail items in an OLM file format. After the Export, click Finish to close the window.

How to Import OLM Files to Outlook for Mac or Windows

You can easily import the OLM file in another Outlook for Mac profile through the ‘Import’ wizard available in Outlook for Mac 2011 under File > Import and Outlook for Mac 2016 or 2019 under Tools > Import.

However, you cannot import OLM to Outlook for Windows. Unlike Outlook for Mac, Outlook on Windows supports PST files. Thus, you must convert the exported OLM file to PST by using Stellar Converter for OLM. After conversion, you can easily import the converted PST file to Outlook for Windows via Import/Export wizard.

Conclusion

The software provides an enhanced preview of each email in a three-pane window. You can also select desired mail items from the OLM file and save them into a PST file. Thus, you can filter the mailbox and get rid of emails or mail items not required anymore.  

The software not only helps you import or migrate emails from Outlook for Mac to Windows, but it also provides options to export the OLM file to Office 365 directly. Again, it gives you more control and options to import and export the data from OLM files to Outlook or Windows, or Office 365.

Besides, you can also save the emails in multiple formats, such as PST, EML, MSG, HTML, RTF, and PDF. This allows you to open the emails in various applications and platforms, including a web browser.   

You can download the demo version and evaluate the Stellar Converter for OLM for free. Once satisfied with the software features and preview of email items, you can activate the software and save the emails from OLM file to PST and other formats or export directly to Office 365.

Hope this helps you understand the OLM Outlook data files. However, if you have any questions or queries related to OLM or OLM to PST conversion, feel free to leave a comment below.

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About The Author

Ravi Singh

Ravi Singh is a Senior Writer at Stellar®. He is an expert Tech Explainer, IoT enthusiast, and a passionate nerd with over 7 years of experience in technical writing. He writes about Microsoft Exchange, Microsoft 365, Email Migration, Linux, Windows, Mac, DIY Tech, and Smart Home. Ravi spends most of his weekends working with IoT (DIY Smart Home) devices and playing Overwatch. He is also a solo traveler who loves hiking and exploring new trails.