PST Files Not Supported in New Outlook for Mac? Here’s How to Open Them [2026]

Ritu Roy | How to's Outlook Software Technology | 7 minutes read | Modified on: 03-11-2026

Summary: In this article, you can understand why New Outlook for Mac does not support PST files and why users may encounter difficulties when trying to import or access their old Outlook archives. We will discuss the limitations of the New Outlook interface, the reasons behind the unavailable PST import option, and different methods to access PST file data on Mac. Furthermore, you will learn about alternative solutions for viewing and managing your important Outlook emails, contacts, calendars, and attachments without compromising your existing mailbox data. Whether you have migrated from Windows Outlook or want to access previously saved PST archives on macOS, this guide will help you find a suitable approach.

Why Are PST Files Not Supported in New Outlook for Mac?

PST (Personal Storage Table) is a file format traditionally used by Microsoft Outlook on Windows to store emails, contacts, calendars, attachments, and other mailbox information. Classic Outlook for Windows uses MAPI-based technology to read and manage these files. However, New Outlook for Mac follows a different architecture, which is why it does not offer native PST file support.

Unlike the traditional Windows version, New Outlook for Mac mainly focuses on cloud-based email services and synchronization. It relies on modern Microsoft services and APIs to manage mailbox data rather than handling locally stored PST archives.

Here are some major reasons behind this limitation:

  • Cloud-Based Synchronization: New Outlook for Mac primarily uses Microsoft cloud services and modern APIs to synchronize mailbox data across devices. Its design focuses on online accounts rather than importing local PST archives.
  • Changes in Data Storage Architecture: The new application uses cloud-connected storage systems such as Exchange, Microsoft 365, Gmail, and IMAP accounts. It does not provide the same local file management capabilities available in Classic Outlook for Windows.
  • PST Format Compatibility: PST is a Microsoft-specific binary file format that requires dedicated parsing support. Unlike Windows Outlook, New Outlook for Mac does not include the necessary built-in functionality to open or import these files directly.
  • Different Archive Formats on Mac: Outlook for Mac has traditionally used OLM files for exporting and archiving mailbox data. It also works with common email formats such as EML and MBOX through supported applications and workflows. However, these formats are not direct replacements for PST files.

Because of these architectural differences, users cannot directly open or import PST files into New Outlook for Mac using its standard interface. They need to explore alternative methods to access their previously saved Outlook data.

Manual Methods and Their Limitations

If you want to access PST files in New Outlook for Mac, there are a few manual workarounds you can try before choosing a third-party solution. These methods involve using an older version of Outlook for Mac or transferring PST data through a Windows computer and an online mailbox. However, each approach has certain limitations that users should consider.

Method 1: Switch Back to Legacy Outlook for Mac

Legacy Outlook for Mac provides a built-in import option that allows users to import Windows Outlook PST files. After importing, the mailbox data can be accessed through the local On My Computer folders.

Steps to Import PST Files:

  1. Launch Microsoft Outlook on your Mac.
  2. Click the Help option from the macOS menu bar.
  3. Select the Revert to Legacy Outlook option, if available.
  4. Once Legacy Outlook starts, click File and select Import.
  5. Select Outlook for Windows archive file (.pst) and click Continue.
  6. Locate the PST file you want to import and follow the on-screen instructions to complete the process.

Limitations:

  • Limited Availability: Microsoft is gradually phasing out Legacy Outlook, so this option may not be available in all Outlook versions.
  • Local Folder Restrictions: Imported mailbox data is generally stored in the On My Computer folders. These local folders may not be accessible when switching back to New Outlook.
  • Import Performance: Importing large PST files can take considerable time and may cause application performance issues.
  • Compatibility Concerns: Changes in macOS and Outlook updates may affect the availability and functionality of Legacy Outlook.

Method 2: Upload PST Data Through a Windows PC or IMAP Account

Another way to access PST data in New Outlook for Mac is to use a Windows computer with Classic Outlook. You can import the PST file into Windows Outlook and then transfer its contents to a supported online mailbox, such as Microsoft 365 or an IMAP account.

Steps to Transfer PST Data:

  1. Launch Classic Microsoft Outlook on your Windows computer.
  2. Add the PST file to Outlook using the Open & Export or Import/Export option.
  3. Add your Microsoft 365 or compatible IMAP email account to Outlook.
  4. Copy or move the required email folders from the PST file into the configured mailbox.
  5. Allow Outlook to upload the selected emails and folders to the mail server.
  6. Open New Outlook for Mac and sign in using the same email account to access the synchronized messages.

Limitations:

  • Storage Restrictions: Large PST archives may exceed the available mailbox storage quota.
  • Time-Consuming Process: Uploading several gigabytes of mailbox data can take hours or even longer, depending on internet speed.
  • Metadata Changes: Some Outlook-specific properties, such as custom views, categories, flags, and calendar information, may not transfer as expected.
  • Synchronization Issues: Network interruptions, server limitations, or connection timeouts can interrupt the upload process.
  • Additional Requirements: This method requires access to a Windows computer, a configured email account, and sufficient cloud storage.

Note: These manual approaches may work for certain users, but they are not always convenient for accessing large PST archives on a Mac. Consider the file size, available storage, and required mailbox information before choosing either method.

Apply a Reliable Alternative Solution

If the manual methods seem complicated or fail to provide the desired results, converting PST files into a Mac-compatible format is another option. For this purpose, users can try CubexSoft PST Converter for Mac, which helps convert Windows Outlook PST files into formats supported by Mac-based email applications.

win download buynow

mac download buynow

The software allows users to process PST files on both Intel and Apple Silicon Macs, including M1, M2, and M3 devices, without installing Microsoft Outlook or setting up a Windows virtual machine. Users can add their PST files, select the required output format, and save the converted mailbox data to their preferred destination. It provides an alternative for those who want to access their old Outlook email archives on macOS without depending on the limited import functionality of New Outlook for Mac.

Step-by-Step Guide to Convert PST Files for New Outlook on macOS

Step 1: Add PST Files to the Software

  • Download the CubexSoft PST File Converter and launch it on your Mac.
  • Click the Add File(s) option to select individual PST files or choose Add Folder to load multiple files at once.
  • Once the files are added, the software will scan them and display the available mailbox folders in a tree structure on the left panel.
  • Select the required folders and review their contents before proceeding with the conversion.

Step 2: Select the Desired Output Format

After loading the PST files, navigate to the Select Saving Options dropdown menu and choose the format according to your requirements.

  • OLM: Select this format if you want to access converted mailbox data through Outlook for Mac.
  • MBOX/EML: Choose either format to transfer emails into Apple Mail or other compatible email clients.
  • Office 365/IMAP: Select this option if you want to migrate PST mailbox data directly to a supported cloud account.

Step 3: Start the Conversion Process

  • Configure Settings: Choose the required options and specify the destination location, wherever applicable.
  • Begin Exporting: Click the Export button to start processing the selected PST files.
  • Monitor Progress: The application will display the conversion status while processing the mailbox data.
  • Check the Results: Once the process finishes, review the generated report to verify the exported data.

How to Import Converted Data into Mac Applications?

After converting the PST files, follow the appropriate steps to access your mailbox data in the desired Mac application.

For Apple Mail (MBOX/EML Format)

  1. Open the Apple Mail application on your Mac.
  2. Click File from the menu bar and select Import Mailboxes.
  3. Choose Files in mbox format and click Continue.
  4. Browse to the folder containing the converted MBOX files.
  5. Select the required files and proceed with the import.
  6. Once completed, access the imported emails from the Import section in the Apple Mail sidebar.

For Outlook for Mac (OLM Format or Cloud Migration)

  • Using OLM Files: Open Outlook for Mac, navigate to Tools > Import, select the exported OLM file, and follow the on-screen instructions. After importing, your mailbox folders and emails will become available in Outlook.
  • Using Direct Cloud Migration: If you have transferred your PST data to a supported Microsoft 365 or IMAP account, open New Outlook for Mac and sign in with the same account. Allow the mailbox to synchronize so that the uploaded emails and folders become available.

Epilogue

New Outlook for Mac does not provide native support for importing PST files, which creates difficulties for users who want to access their old Windows Outlook archives. Although switching to Legacy Outlook or transferring data through an IMAP account can help in certain situations, these approaches may involve additional steps and compatibility limitations.

Converting PST files into a Mac-compatible format offers another way to access archived mailbox data. By selecting the appropriate output format, users can move their emails into supported Mac applications without relying on the direct PST import feature. The right approach depends on the application you want to use and how you plan to manage your existing Outlook data.