Our organization is preparing for a large-scale Microsoft 365 migration and needs to migrate hundreds of Exchange Online Public Folders to Shared Mailboxes before the 2026 EWS restrictions take effect. We're concerned about preserving folder hierarchy, emails, permissions, and minimizing downtime during the migration. What approach would you recommend?
Michael Anderson
Enterprise Messaging Administrator
Public folders have long enabled multiple teams in an organization to share email messages, calendar availability, and contact information, using Exchange Online Public Folders. Microsoft is increasingly simplifying our access to the service, and the continued modernization of Microsoft 365 means these traditional feature types are becoming antiquated and limited in capabilities. This is evident by the limitations Microsoft started applying on access and usage of Exchange Online Public Folders in 2026 in an effort to migrate public folders to shared mailboxes and other modern platforms.
In this article, we'll explore both manual and professional methods to complete the migration, along with their advantages and limitations. We'll also introduce the Aryson Office 365 Backup & Restore Tool, a reliable solution that simplifies the migration process with minimal manual effort.
Exchange Online Public Folders use Exchange Web Services (EWS), a legacy technology that Microsoft eventually phased out, moving on to Microsoft Graph and the new Microsoft 365 collaboration solution.
Starting on 01 October 2026, EWS connections in Exchange Online will be blocked by Microsoft. This means clients relying on EWS will be blocked from connecting, while users will continue to access the public folders from an Outlook-supported client.
The EWS API for public folder item creation, deletion, read, and update will be deprecated after October 2026. Custom apps, automation scripts, or third-party solutions that utilize the EWS API to access public folder items would be affected by this statement.
We advocate that everybody within an organization adopt shared mailboxes, Microsoft 365 groups, Teams, SharePoint, and Microsoft Graph. They provide a modern, stable, safe, and reliable replacement for the legacy public folder model.
Shared mailboxes provide a practical option for organizations moving away from legacy public folders. When the migration also involves moving existing mailboxes between Microsoft 365 environments, the Exchange Online (Microsoft 365) to Exchange Online Migration process should be planned alongside the public folder transition to maintain data continuity.
The manual way is inefficient and slow. Migrations of this type would work best in situations where there are only a limited number of public folders or an organization has a small scale of information. Organizations that store considerable data or contain many public folders definitely need to invest in a migration service or a tool for reliable, faster, and secure migration. The Aryson Office 365 Backup & Restore tool supports migrating each public folder to Microsoft 365 Shared Mailboxes, keeping folder hierarchy, emails & every mailbox's contents intact. It can also export Office 365 mailbox to PST.
Migration of data between the source and destination Microsoft 365 accounts is done smoothly and efficiently with a high sense of security by our tool. With our unique automated system, users can migrate primary mailboxes, public folders, and online archives with minimal effort and downtime. You can also export Office 365 data to CSV for analysis and record-keeping.
Key reasons to choose the tool include:
There are plenty of professional migration tools designed to facilitate the migration of public folders to Microsoft 365 shared mailboxes. Depending on their nature, each software has varying features and automation strategies. Compare below the features of the Aryson Office 365 Backup & Restore Tool with some others:
| Features | Aryson | BitTitan |
|---|---|---|
| Public Folder to Shared Mailbox Migration | ||
| Multiple Microsoft 365 Workloads | ||
| Free Trial Version | ||
| Date Range Filter | ||
| Bulk Migration | ||
| Preserves Folder Hierarchy | ||
| Simple User Interface | Moderate | |
| Starting Price | $99 (Single User License) | $114 per 10 GB for public folder migration |
A multinational organization consisting of more than 800 Microsoft 365 users was planning for the Exchange Online changes and looking to export public folders to Office 365 shared mailboxes across several departments. Since public folder data was their business's critical source for shared emails, calendars, and contacts, maintaining data consistency and ensuring business operations remained a top priority in their strategy. In this process, we used the Aryson Office 365 Backup & Restore Tool to migrate public folder data without any changes. The process went through various phases without any downtime, thereby ensuring continuous access to data for all users.
Many organizations have utilized the functionality available in Exchange Online Public Folders, and with a 2026 change to Exchange Web Services restrictions, now is the time to start exploring more modern Microsoft 365 collaboration features. The native option works for a few simple transfers of small email data but requires extensive manual configuration to migrate large data.
To migrate public folders to shared mailboxes effectively, businesses can use the Aryson Office 365 Backup & Restore Tool, an intelligent utility that makes migration simple, minimizes risks and downtime, and prevents future compatibility challenges, all while preparing the business to adopt Microsoft’s collaboration strategy.
Is the Aryson Office 365 Backup & Restore Tool suitable for large Microsoft 365 enterprise migrations?
Ans. The tool is designed to handle both small and large-scale Microsoft 365 migrations. Its bulk migration capabilities, advanced filters, and user-friendly interface make it suitable for enterprise environments with large volumes of data.
Can I migrate emails without transferring their attachments?
Ans. The Aryson Office 365 Backup & Restore Tool provides a Save Mail Without Attachments option, allowing you to migrate only the email messages while excluding attachments. This feature is useful when you want to reduce storage usage, speed up the migration process, or transfer only the email content for archival or compliance purposes.
Can I migrate public folders without affecting users' daily work?
Ans. Not as live, working conversations. Some tools export chat Yes. The tool is designed to minimize downtime during migration, allowing organizations to plan and execute migrations with minimal disruption to business operations.
Can I migrate only the last 6 months or 1 year of public folder data?
Ans. You can use the built-in date filter to migrate data from a specific time period, such as the last 6 months or the last year, instead of transferring the entire public folder.
Besides Public Folders, what other Microsoft 365 data can I migrate?
Ans. The software also supports migrating primary mailboxes, online archives, and Office 365 to PST and PDF, and other file formats.
Will the software preserve my public folder hierarchy after migration?
Ans. Yes. The tool maintains the original folder hierarchy, ensuring that all migrated data is organized in the destination shared mailboxes just like the source.
How can I avoid migrating duplicate emails when transferring public folders to shared mailboxes?
Ans. The tool includes a duplicate handling feature that helps identify and skip duplicate items during migration. This ensures that unique emails and other mailbox data are migrated, reducing storage consumption and maintaining a clean destination shared mailbox.
What does the "Map Data with Default Folder" feature do?
Ans. This feature automatically matches mailbox items with their corresponding default Microsoft 365 folders during the backup or restore process. It ensures that emails are organized in their proper locations instead of being placed in custom or miscellaneous folders.
How can I free up storage space in my Microsoft 365 mailbox after taking a backup?
Ans. The Free Up Server Space feature allows you to remove emails from your Microsoft 365 mailbox after they have been successfully backed up. This helps reduce mailbox storage usage while keeping a secure copy of your data on your local system or chosen backup location.
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