Old Outlook for Mac loses Microsoft 365 email in October
Reviewed by Helen Jones
Microsoft says the legacy Outlook for Mac app will stop connecting to Exchange Online mailboxes from October 2026. That client still uses Exchange Web Services, a mail connection method Microsoft will retire on 1 October 2026. Microsoft reports that more than 95 percent of Microsoft 365 users have already moved to the current Outlook for Mac. Work and personal Microsoft 365 accounts on the old Mac client lose support at that cutoff. On-premises Exchange mailboxes can keep using the legacy app until 9 October 2029. Users switch by turning off the Legacy Outlook toggle, or by checking for updates in Help or the Apple App Store if the toggle is missing. Admins can still block some current Outlook features with policy.
For years, a Mac user could keep the older Outlook layout and still reach Microsoft 365 email. Inbox, calendar, and flags stayed in a familiar window even as Windows Outlook and Teams kept changing around them. That path now has a date. After EWS goes away, the old Mac client will not fetch Exchange Online mail at all. This is not a gentle prompt to try a new ribbon. It is a hard stop for anyone still on the leftover Mac version, while most colleagues already moved without noticing.
Analysis
This is a change to act on only if you still use Outlook on a Mac. Open Outlook, look for the Legacy Outlook switch, turn it off or run Check for Updates, then send yourself a test message so you know mail still arrives before October.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "Old Outlook for Mac loses Microsoft 365 email in October", Collab365 Spaces. 2 sources referenced.