Microsoft began disabling Exchange Web Services (EWS) by default in Exchange Online today, October 1, 2026. That cuts off the protocol that Apple Mail and Calendar on Mac still use to sync Microsoft 365 work accounts. Mac users on affected accounts may find their work email and calendar no longer updating.
Microsoft stopped adding new features to EWS back in 2018 and announced in 2023 that it would start disabling the protocol in Exchange Online from October 2026. A post updated in June calls the change a phased rollout, which means some Mac users could lose access sooner than others.
Microsoft Is Turning Off EWS in Phases, So Not Every Mac Will Break at Once
Organizations that chose to keep EWS running are not affected for now. Everyone else is on the clock, and the cutoff may not land on the same day for every tenant. IT administrators can still restore access, but only until Microsoft pulls the plug for good.
The key dates are spread over nearly a decade, and the final one is the one that matters most:
- 2018: Microsoft stops adding new features to EWS
- 2023: Microsoft announces EWS will start being disabled in Exchange Online from October 2026
- October 1, 2026: EWS is disabled by default in Exchange Online, rolled out in phases
- April 1, 2027: EWS is shut down in Exchange Online permanently, with no extensions currently planned
The change only touches Microsoft’s cloud-hosted email service, so the impact depends on how a company runs Exchange. Companies that run their own Exchange servers are not affected. iPhone and iPad are also safe, since they sync through Exchange ActiveSync instead of EWS.
Apple Says Microsoft Graph Support Is Coming, but No macOS 27 Update Has Delivered It
In an Apple Platform Deployment support document, Apple says it is “actively working with Microsoft” to move Mail, Calendar, Contacts, Notes, and Reminders on Mac to the newer Microsoft Graph API in a future macOS 27 update. That covers five apps, so a Mail-only fix is not what Apple is describing.
Apple skipped the macOS 27.1 betas entirely, and the release notes for the macOS 27.2 betas make no mention of Graph support. The update has not reached Macs yet.
Until Apple delivers it, affected organizations have two options. They can keep EWS running, or they can move Mac users to a Graph-compatible client such as Microsoft’s Outlook app. Neither is a long-term answer for Mac users who prefer Apple Mail, since the EWS option expires on April 1, 2027.
