Microsoft is Retiring EWS: What It Means for Your Public Folder Backup

Topic

This article discusses Microsoft's retirement of Exchange Web Services (EWS) and its impact on public folder backup.

Environment

NinjaOne SaaS Backup
Microsoft Exchange Web Services (EWS)

Description

Microsoft has announced that Exchange Web Services (EWS) will be deactivated by default starting on October 1, 2026, and fully retired on April 1, 2027. EWS is the API that many third-party products, including NinjaOne, use to back up Exchange data. For Microsoft’s full announcement, refer to: Deprecation of Exchange Web Services in Exchange Online. (external link)

Over the past year, NinjaOne has migrated nearly all services that used EWS to the Microsoft Graph API. Core email and Exchange backup functions moved earlier this year and are running stably. The remaining feature that depends on EWS is public folder backup. Once Microsoft retires EWS, NinjaOne will no longer be able to back up or protect public folder data.

What you can do during the transition

To make the transition as smooth as possible, note the following points and take action as needed.

Starting October 1, 2026, Microsoft will deactivate EWS by default. To let NinjaOne keep protecting your public folder data, re-enable EWS in the Microsoft admin center. NinjaOne’s Microsoft app must also be on the EWS allow list. For most customers, this happens automatically and requires no action. If you run into issues, follow the instructions in our Microsoft Exchange Web Services (EWS) Deprecation document, or open a support ticket.
With EWS activated, public folder backup and restore will continue to work until Microsoft fully retires the service. Some organizations will be prompted to re-authenticate so we can acquire the updated permissions needed during the transition.
On April 1, 2027, Microsoft will shut down EWS completely, and NinjaOne will lose access to it. Your existing public folder backups remain available, but no new backups will be created.
If EWS is deactivated at the tenant or account level, NinjaOne cannot access public folder data. Backups will stop, and you will not be able to restore public folder data to a public folder. You can still migrate backed-up data to other mailbox types, such as standard or shared mailboxes.
We recommend moving from public folders to shared mailboxes. Shared mailboxes offer similar functionality, and NinjaOne fully supports backup and restore for them.

Microsoft has not announced a shutdown of public folders themselves, only the EWS API used to access them. If Microsoft releases a new API that supports public folders, we will evaluate it and update you.

Additional Resources

For more information about EWS deprecation, refer to Microsoft Exchange Web Services (EWS) Deprecation.

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