Exchange users on a Mac need a plan until Apple's Mail update arrives

Microsoft began disabling Exchange Web Services (EWS) in Exchange Online on October 1 for tenants that had not explicitly chosen to keep it enabled. EWS is the connection Apple's Mac apps use for Exchange accounts; iPhone and iPad use Exchange ActiveSync instead.

Apple says it is working with Microsoft to move Mail, Calendar, Contacts, Notes, and Reminders on the Mac to the Microsoft Graph API in a future macOS 27 update, including a declarative configuration for device management services. It has not given a date.

This does not mean every Exchange account on a Mac stopped working this month. Whether you are affected depends on your organization's settings.

Decide the stopgap with IT, not on your own

Our take: if Mail or Calendar stops syncing a work or school account, ask your administrator before switching apps. Microsoft lets admins temporarily re-enable EWS, which may keep Apple's apps connected until the update ships.

That window is fixed. Microsoft says EWS will be fully and permanently disabled on April 1, 2027, with no extensions. Organizations that rely on Apple's built-in apps should have an alternative client ready in case the macOS update arrives late.

Primary Sources

• Apple Platform Deployment: Integrate with Microsoft Exchange
• Microsoft Exchange Team: Exchange Online EWS, Your Time is Almost Up