How to Migrate Public Folder to Shared Mailbox in Office 365

Written By Khushboo Maurya
Updated on September 24th, 2026

ⓘ Fact-checked and reviewed in accordance with our Editorial Policy

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Public folders have been useful for many years, but they were not built for mobile phones or easy licensing. Today, many teams use phones and browsers for email. Therefore, many administrators choose to move folder to shared mailbox. This change removes limits on Outlook and saves money on licenses. This guide shows the reasons for moving and the exact steps to finish the move in Office 365.

TL;DR: Migrate public folder to shared mailbox is needed if you want to open the mailbox on a device. You can move the data manually or with a professional tool that makes the move easier.

A Question Many Admins Ask

“We still use folders in our Exchange Online tenant but our team wants to access shared data from Outlook mobile. How can we convert folder to shared mailbox in Office 365 without losing emails, permissions or folder structure?”

This is a normal situation for groups that set up public folders many years ago and now want something that works better on phones. The rest of this article explains why & how.

Table of Contents

Why Convert Public Folder to Shared Mailbox

Public folders and shared mailboxes have the same goal: they let a group share one space instead of sending emails back and forth. They act in different ways.

*Aspect*	*Public Folder*	*Shared Mailbox*
*Mobile access*	Limited or unavailable natively	Fully supported in Outlook mobile
*Licensing*	Included with Exchange Online plans	No separate license needed
*Structure*	Deep folder hierarchy	Flat mailbox with folders
*Storage limit*	Large capacity, spread across mailboxes	50 GB without a license, up to 100 GB with an added plan
*Ease of setup for new users*	Requires folder-level permission planning	Simple to add as an additional mailbox in Outlook

Organizations usually pick to migrate Exchange Online public folders to shared mailbox when they want simpler access on all devices. When they want to stop rely on the old public folder setup & when they want fewer mailboxes to manage. Microsoft has already announced that it will not support Exchange Web Services (EWS) in Exchange Online. EWS is used by public folder tools. So now is a time to plan the move instead of waiting.

This move is not right for every group. If your public folder data is larger than a shared mailbox can. If your team needs the many layers of folders that public folders give you might keep the public folder structure and move it to a new public folder system instead of a shared mailbox.

Before You Begin: Points to Check

An Office 365 public folder to shared mailbox migration needs a few things ready first:

The account that does the move must have a valid licensed mailbox & full rights to the shared mailbox that will receive the data.
Check how big the folder you plan to move is. If it is bigger than a shared mailbox split the data into than one shared mailbox before starting.
Write down who can see the folder now so you can give the same people access to the shared mailbox later.
Export the public folder data to a file before the live move in case you need to restore or double-check.

You can read Microsoft’s notes on public folders in Exchange Online for more details on limits & client support before the move.

How to Migrate Public Folders to Office 365 Shared Mailbox

You will see the steps that help you to move your data from public folder to shared mailboxes.

Step 01: Create the Destination Shared Mailbox

The shared mailbox must exist before any data is moved. You can create it in the Microsoft 365 admin center or, in the Exchange admin center:

Sign in to the Microsoft 365 admin center. Then go to Teams and Groups. After that select mailboxes.
Select Add a shared mailbox, then enter a display name & email address.
Save the changes, then add the users who should have access once the migration is complete.

Microsoft’s guide on creating a shared mailbox covers this in detail, including how automapping and permission assignment work.

Step 2: Assign Full Access Permission

Grant the admin account & the intended users full access permission to the shared mailbox. Without that permission the content that has been migrated will not be visible or usable once it reaches the shared mailbox.

Step 3: Export the public folder content to a PST file

This is the core of the migration. The public folder content must be pulled out into a PST file before it can be placed into the shared mailbox. You can do this manually using Outlook’s export feature or by using eDiscovery search and export in compliance‑heavy environments. If the folder structure is large or complex you might use a backup and export tool.

For a step-by-step explanation of this part, check out our guide: Export Public Folder to PST.

Step 4: Import the PST into the shared mailbox

Once the PST file is ready you can bring it into the shared mailbox via Outlook. You have to simply drag the folders into the shared mailbox. If the data set is large use the PST import service in the Microsoft 365 compliance center. During this step recreate the folder names so the structure stays clear & recognizable for your team.

Step 5: Recreate permissions. Verify data

After the import finishes, assign the same access rights that existed on the original public folder to the relevant users on the shared mailbox. Open a few folders to confirm that the emails, attachments, & dates have carried over correctly before retiring the public folder.

If your longer‑term plan also involves moving an existing shared mailbox into Office 365 from another environment our guide on Migrate Shared Mailbox to Office 365 covers that process separately.

A professional method for larger or sensitive migrations

Export and import works well for small public folders but larger environments with several gigabytes of mixed content – emails, calendars, contacts – often benefit from a dedicated backup tool instead of relying only on Microsoft’s own export options.

Cigati Exchange Server to PST Backup Tool is designed to back up primary, shared, public folder, and archive mailboxes in one pass while keeping the original folder hierarchy intact.

This approach is useful as a safety step: it lets an administrator hold a verified organized copy of the public folder data on hand before making any change to the source environment, which reduces the risk of losing information partway through a migration.

Download Now Purchase Now

Transfer mailbox data from Exchange Server to PST with ease.
Keep the folder structure intact during the whole process.
Support both single-user login and admin impersonation for access.
Send data to Office 365. Save it directly as a PST file.
Remove duplicate emails by checking sender, recipient, subject and message body.
Once items are backed up, shift items to the Bin to free up mailbox space for data.
Allow you to rename folders at the destination for organization.
Let you limit the backup to a date range.
Recognize items already backed up in sessions and skip them cutting down processing time on future runs.
Give you control over which item types to include, such as emails, contacts or calendar entries.
Let you pick the location where PST files are saved.
Split PST files into smaller easier-to-manage parts when the Split PST option is turned on.
This software is available, for both operating systems, Windows & Mac.

To know how this software helps to move your data. Just look at the step-by-step guide for a clear understanding of the software.

Note: Whether you choose an export or a dedicated backup utility the underlying goal stays the same: have a complete checked copy of the data before the public folder is retired or converted.

Conclusion

Choosing to move folders to a shared mailbox is mostly about fitting with how your organization currently works: being able to access things on the go having simpler licensing and easier everyday management. Think about storage limits, permissions and making sure there is a backup step. This will make the whole process more predictable.

Frequently Asked Questions

Q1. Can a public folder be migrated directly into a shared mailbox without exporting to PST first?

Ans. Native Microsoft tools do not offer a single‑step conversion between the two mailbox types. The export‑then‑import approach or a third‑party migration tool is currently the path.

Q2. Will calendar items and contacts also migrate along with emails?

Ans. Yes long as the export step includes those item types. Review the export settings before running the job so nothing gets left out.

Q3. Do I need a license, for the shared mailbox?

Ans. No. Shared mailboxes do not require a license as long as their size stays within the free storage limit.

About The Author:

Khushboo Maurya

Khushboo Maurya is a digital content and SEO professional focused on creating useful, search-friendly content that connects with the right audience. She specializes in content optimization, website growth, and practical SEO strategies that improve visibility, engagement, and organic reach.