Microsoft 365 Work Accounts May Stop Syncing in Apple Mail
Beginning Oct 1 2026, Microsoft is turning off EWS by default in Exchange Online, the legacy API that macOS Mail, Calendar, Contacts, Notes and Reminders still use to sync corporate 365 accounts. The move follows Microsoft’s 2018 decision to stop adding features to EWS and its 2023 announcement that the protocol would be retired. Organizations that explicitly keep EWS enabled are exempt for now, but most will see the connection drop as Microsoft rolls out the change in stages. IT admins can temporarily restore access, but the final cut‑off on Apr 1 2027 is non‑negotiable. The impact is limited to cloud‑hosted Exchange; on‑prem Exchange servers and iOS/iPadOS devices, which rely on Exchange ActiveSync, remain unaffected. Apple has acknowledged the issue and says it is collaborating with Microsoft to shift macOS native apps to the newer Microsoft Graph API, but the promised macOS 27 update has not materialized—Apple skipped the 27.1 betas and the 27.2 notes contain no Graph reference. In the interim, enterprises can either keep EWS running or migrate Mac users to a Graph‑compatible client such as Microsoft Outlook for Mac.
The shutdown reflects a broader industry shift toward unified, cloud‑first APIs. Microsoft has been consolidating its developer surface around Graph since 2020, positioning it as the single gateway for mail, calendar, contacts, and Teams data. Apple’s reliance on EWS for macOS native apps has become a liability, especially as Microsoft accelerates Graph’s feature set while deprecating older endpoints. Competitors like Google already expose their mail services through modern REST APIs, and Outlook’s cross‑platform presence gives Microsoft a ready alternative for Mac users. Apple’s lag in delivering Graph support could push corporate users toward Outlook or third‑party clients, eroding the perceived advantage of native macOS apps.
Enterprises should treat the phased EWS disablement as a hard deadline for migration planning. Immediate actions include auditing which Mac users still depend on Apple Mail, testing Outlook or other Graph‑enabled clients, and confirming that EWS is not inadvertently locked down by policy. Watch for any Apple announcements tied to macOS 27 or a possible emergency patch, and monitor Microsoft’s rollout timeline for any extensions or exceptions that could affect compliance or service‑level agreements.
Key Takeaways
Microsoft’s default EWS shutdown begins Oct 1 2026, with a final April 1 2027 cut‑off that will break macOS native mail sync for most 365 tenants.
Apple has not yet delivered the promised macOS 27 Graph integration, leaving Mac users reliant on Outlook or a temporary EWS exemption.
The change forces IT departments to audit and migrate Mac mail clients now, rather than waiting for a future macOS update.
Organizations running on‑prem Exchange or using iOS/iPadOS devices are insulated from the disruption, highlighting the uneven impact across device ecosystems.
About the Source
This analysis is based on reporting by MAC Rumors. Here is a short excerpt for context:
From October 1, 2026, Microsoft began disabling Exchange Web Services (EWS) by default in Exchange Online, which will cut off the protocol that Apple's Mail and Calendar apps on Mac still rely on to sync Microsoft 365 work accounts. The cutoff has been on the cards for a fairly long time, as Microsoft stopped adding new features to EWS back in 2018, while in 2023 it announced that it would start disabling the protocol in Exchange Online from October 2026. recently updated post from June, Microsoft described the change as a "phased rollout," so some Mac users could lose access sooner than others. It's still possible for IT administrators to restore access. However, Microsoft plans to shut down EWS in Exchange Online permanently on April 1, 2027, and no extensions are currently planned. support document, the company says it is "actively working with Microsoft" to move Mail, Calendar, Contacts, Notes, and Reminders apps on Mac to the newer Microsoft Graph API in a future macOS 27 update. Except, that update hasn't arrived yet. Apple skipped macOS 27.1 betas entirely, while release notes for the macOS 27.2 betas have yet to make any mention of Graph support. Meanwhile, affected organizations can just keep EWS running or move Mac users to a Graph-compatible 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 run their own Exchange servers aren't affected. Neither will iPhone and iPad be impacted, since they use Exchange ActiveSync rather than EWS. (Thanks, Jonathan!) Tags: Apple Mail, Microsoft 365 This article, "Microsoft 365 Work Accounts May Stop Syncing in Apple Mail" first appeared on MacRumors.com Discuss this article in our forumsRead the original at MAC Rumors
