Still Using Legacy Outlook for Mac? Plan Your Switch Now

If anyone on your team uses Outlook on a Mac, it is worth a quick check this month. Starting in October 2026, Microsoft is retiring the connection that legacy Outlook for Mac uses to reach Microsoft 365 mailboxes. Once it is switched off, legacy Outlook stops syncing: no new email, no calendar updates, no contacts.

Who is affected

Only people who still have the "Legacy Outlook" toggle turned on in the top-right corner of Outlook for Mac. Most Microsoft 365 users moved to the current version some time ago, so this usually catches the few who had a reason to stay. Windows users are not affected. If your mailboxes live on your own Exchange server rather than in Microsoft 365, the timeline is longer (support runs to October 2029), but the direction is the same.

What the switch involves

For most people, turning off the Legacy Outlook toggle is all that's needed; the app reloads in the current version. If there is no toggle, the app needs an update first (Help, then Check for Updates). A few things are worth checking afterwards: email signatures may need reformatting, saved searches may need to be recreated as Smart Folders, and local folders can take a while to transfer, so let that finish before closing the app.

Why plan it rather than wait

The switch takes seconds. Leaving it means a morning where mail stops arriving, and nobody knows why, multiplied by everyone who hits it at once. Legacy Outlook also no longer receives updates, and software nobody maintains is a gap worth closing.

Not sure who on your team is still on legacy Outlook? Ask us, and we will help you check and make the move on a quiet afternoon.