PSA: Apple Mail on Mac may stop syncing Microsoft 365 accounts today

Microsoft today began disabling Exchange Web Services (EWS) by default in Exchange Online, which will remove the protocol that Apple’s Mail, Calendar, Contacts, Notes, and Reminders apps on Mac still rely on to sync Microsoft 365 work accounts.

This cut has been considered for quite a long time, since Microsoft stopped adding new features to EWS in 2018, while in 2023 it announced that it would start disabling the protocol in Exchange Online from October 2026.

As Microsoft explains in the blog post linked above, organizations that have chosen to keep EWS running are not affected at this time. As with everyone, the cut may not happen all at once. In a newly updated post in June, Microsoft described the change as a “phased rollout,” so some Mac users might lose access sooner than others.

IT administrators can also restore access. However, Microsoft plans to permanently shut down EWS in Exchange Online on April 1, 2027, and no expansion is currently planned.

As expected, Apple is aware of the situation. In an Apple platform deployment support document for IT administrators, the company says it is “actively working with Microsoft” to move its Mac applications to the new Microsoft Graph API in a future macOS 27 update.

Except that this update hasn’t arrived yet. Apple has completely ignored the macOS 27.1 betas, while the release notes for the macOS 27.2 betas have yet to mention Graph support.

Meanwhile, affected organizations can simply keep EWS running or move Mac users to a Graph-enabled client, such as Microsoft’s Outlook app.

Note that the change will only affect Microsoft’s cloud-hosted email server. In other words, companies that operate their own Exchange servers are not affected. The iPhone and iPad won’t be affected either, since they use Exchange ActiveSync rather than EWS.

(Thank you Jonathan!)