Legacy Outlook for Mac End of Support 2026: What to Do & How to Back up Emails
Legacy Outlook for Mac End of Support 2026 is an important update for users who still rely on the classic Outlook app to manage their Microsoft 365 emails. Microsoft is ending Legacy Outlook for Mac connectivity to Exchange Online mailboxes in October 2026. After this change, affected users will no longer be able to send or receive emails through their Microsoft 365 accounts using the old app. Before switching to the new Outlook for Mac, make sure you back up any important emails stored locally.
What Is Legacy Outlook for Mac?
Legacy Outlook for Mac is the classic version of Microsoft Outlook that many users still use to manage their emails. Microsoft introduced a new version of Outlook for Mac but kept the old version available through a switch in the app. Because of this, some users may not realise they are still using Legacy Outlook.
If your Outlook has the older interface or you use “On My Computer” folders to store emails locally, you may still be using the legacy version.
Why Is Legacy Outlook for Mac End of Support 2026 Happening?
Microsoft is ending Legacy Outlook for Mac support for Exchange Online because the classic app relies on an older connection technology called Exchange Web Services (EWS). Microsoft is moving away from EWS in Exchange Online and shifting toward newer technologies used by the new Outlook for Mac.
Once this connection is no longer available, Legacy Outlook will not be able to access affected Exchange Online mailboxes. This means users will no longer be able to send or receive emails through their Microsoft 365 accounts using the classic app. Switching to the new Outlook for Mac before the deadline can help users avoid interruptions.
Also Read- How to Switch Back to Legacy Outlook Mac
What Happens When Legacy Outlook for Mac Stops Working?
If you continue using Legacy Outlook for Mac with a Microsoft 365 or Exchange Online account after the retirement takes effect, you may face several issues:
- Emails will stop syncing: You will no longer be able to send or receive emails through the affected mailbox.
- Calendar and contacts will stop updating: New meetings, appointment changes, and contact updates may no longer sync properly.
- Switching back will not fix the issue: Returning to Legacy Outlook will not restore Exchange Online connectivity after it has been disabled.
- Updates will be limited: Legacy Outlook will no longer receive new features, and ongoing support will be limited.
Organisations using Exchange Server on-premises have more time, with security updates available until October 9, 2029. However, Microsoft 365 users should plan to move to the new Outlook for Mac before the deadline to avoid email interruptions.
How to Protect Local Emails before Switching to New Outlook for Mac?
Most emails stored on Microsoft’s servers should remain safe when you switch to the new Outlook for Mac. However, emails saved in On My Computer folders may not transfer to the new app.
These folders store emails directly on your Mac rather than on the mail server. They may contain old messages imported from PST or OLM archives or emails you moved from your online mailbox for storage.
The new Outlook for Mac does not support On My Computer folders in the same way as Legacy Outlook. As a result, these local emails may not appear after switching, even though the original data has not necessarily been deleted. If you lose access to the old Outlook app, recovering these messages may become more difficult.
How to Check for Locally Stored Emails?
Before moving to the new Outlook for Mac, follow these steps:
- Open Legacy Outlook on your Mac.
- Look for On My Computer in the left sidebar.
- If the section is missing, go to Outlook > Settings > General and make sure Hide On My Computer folders is not selected.
- Check the folders for emails or other important information you want to keep.
If you find locally stored emails, calendars, or contacts, back them up before switching to the new Outlook.
How to Prepare for Legacy Outlook for Mac End of Support 2026?
Before switching to the new Outlook for Mac, it is important to back up your emails and other data. One way to do this is by exporting an OLM file, which is Outlook for Mac’s archive format. It can store supported emails, contacts, calendar events, tasks, and notes in a single file.
Method 1: Export an OLM File
Follow these steps to create a backup of your Outlook data:
- Open Legacy Outlook for Mac.
- Go to File > Export. In some versions, this option may appear under Tools > Export.
- Select the items you want to include in the backup. Choose all available items if you want to export a complete archive.
- Click Continue and choose where to save the OLM file.
- Save the file to a safe location, preferably an external hard drive, and remember where you stored it.
Complete the export while Legacy Outlook can still access your mailbox and local folders. Keep the OLM file safe so you have a backup of your important data before moving to the new Outlook for Mac.
Method 2: Convert OLM Files to Access Your Emails in Other Applications
Exporting an OLM file creates a backup of your Outlook for Mac data, but you may not be able to open it directly in other email applications. If you want to access your old emails in a different email client or move them to another account, you may need to convert the OLM file into a compatible format.
CubexSoft Mac OLM Converter helps users convert OLM files into different formats for easier access, email migration, and long-term storage. Depending on your requirements, you can choose a suitable output format for your archived Outlook data.
With OLM Converter for Mac, you can convert OLM files into the following formats:
- PST: Convert OLM files to PST for use with compatible versions of Microsoft Outlook for Windows.
- MBOX: Export OLM emails in MBOX format for email clients such as Apple Mail and Thunderbird that support importing this format.
- PDF: Save OLM emails as PDF files for easy reading, sharing, and record keeping.
- VCard and ICS: Export supported contacts and calendar data into formats that can be used by compatible applications.
- Email migration: Transfer OLM mailbox data to supported email services, such as Gmail and Microsoft 365, using the available migration options.
How to Switch From Legacy Outlook to New Outlook for Mac?
Once you have backed up your important emails and local data, you can switch to the new Outlook for Mac. Follow these steps to complete the transition:
- Update Outlook: Open Microsoft AutoUpdate and check whether the latest Outlook updates are available. Install any pending updates.
- Open Legacy Outlook: Launch the classic Outlook app on your Mac.
- Turn off Legacy Outlook: Find the Legacy Outlook switch and turn it off to move to the new Outlook interface.
- Wait for your mailbox to sync: Outlook will open the new interface and begin syncing your mailbox data from the server. Large mailboxes may take longer to load.
- Check your data: Make sure your email folders, calendar events, contacts, signatures, rules, and shared calendars are available. Some settings may need to be configured again.
If the Legacy Outlook switch is missing, check that Outlook is updated and whether you are already using the new interface. The available options may vary depending on your Outlook version and account.
Remember that emails stored on Microsoft’s servers should sync to the new Outlook when you sign in with the same account. However, local emails saved in On My Computer folders may not transfer automatically. You may need to use your OLM backup and a compatible conversion tool to access or migrate that data.
Frequently Asked Questions
1. When Will Legacy Outlook for Mac Stop Working?
Microsoft plans to end Legacy Outlook for Mac connectivity to Exchange Online mailboxes in October 2026. Users should prepare to switch to the new Outlook before the deadline.
2. What Should I Do Before Switching to New Outlook for Mac?
Back up your important emails, especially those stored in On My Computer folders. Exporting your local data to an OLM file can help you keep a copy of emails that may not transfer automatically.
3. Will My Old Emails Disappear After Switching to New Outlook?
Emails stored on the mail server should sync when you sign in to the new Outlook with the same account. However, local emails stored in On My Computer folders may not appear in the new app.
4. How Can I Access My Old OLM Backup?
You can use an OLM-compatible tool, such as Mac OLM Export, to convert your backup into a supported format. The right format depends on the email application you want to use.
5. Does This Change Affect Outlook for Windows?
This retirement specifically affects Legacy Outlook for Mac connecting to Exchange Online. It does not mean Outlook for Windows will stop working because of this same change.
Final Words
The Legacy Outlook for Mac End of Support 2026 update means Mac users need to prepare for the switch to the new Outlook before October 2026. While most server-stored emails should sync automatically, messages saved in On My Computer folders may not transfer to the new app. To protect important emails, export your local mailbox to an OLM file before switching. If you need to access your backup in another email application, Mac OLM File Converter can help convert OLM files into supported formats for easier access and migration. Taking these steps in advance will help keep your email data safe during the transition.
