Is Your Microsoft 365 Backup Still Working? Microsoft Is Shutting Off EWS

Here is a change most business owners will never hear about until something breaks. Microsoft is retiring Exchange Web Services (EWS) in Microsoft 365. EWS is an older “back door” that outside programs have used for years to read and work with mailboxes, calendars and contacts.

Starting in October 2026, Microsoft began switching EWS off for Microsoft 365 organizations, unless an administrator has specifically allowed the apps that still need it. That allowance is temporary: Microsoft plans to permanently disable EWS beginning April 1, 2027.

What might break

Microsoft’s own apps are being moved off EWS. The risk is everything else that connects to your email:

• Microsoft 365 backup tools, especially older ones. This is the big one. A backup that silently stops is worse than no backup, because you think you are covered.
• Email archiving and compliance tools
• CRM systems that log emails or sync calendars
• Scheduling, booking and dispatch software
• Email migration and import/export utilities

Not affected: an Exchange server you run in your own office. This change is for Microsoft 365 (Exchange Online).

What to do this month

1. Check your Microsoft 365 backup. Look at the last successful run. Better yet, restore a test email or calendar item to prove it works.
2. Watch for new errors in any program that connects to Outlook or your calendar: sign-in prompts, missing appointments, “unable to connect.”
3. Ask your software vendors one question: “Have you moved from EWS to Microsoft Graph?” If the answer is no or “we’re working on it,” plan a replacement before April 2027.
4. Review the EWS usage report in the Microsoft 365 admin center to see which apps still use it.

We will check it for you

Managed clients: we are reviewing your tenants and testing restores. If you are not sure whether your email backup is current, Call us at 620-960-8711. We can review it in one visit. Learn more about our backup and disaster recovery service.

Sources: Office 365 for IT Pros: The final countdown to remove EWS · TechRadar