-
Written By
Simran Bhatia -
Approved By
Sonika Rawat -
Updated on
November 11th, 2026 -
Read Time
6 minutes
Migrate Legacy Public Folders to Exchange Online: IT Admin Guide
Fact-checked and reviewed in accordance with our
Editorial Policy
User Query: “Our mailboxes are already in Microsoft 365, but our public folders are still on Exchange 2010. How can I migrate legacy public folders to Office 365 without losing data or permissions?”
Introduction: Your company still has public folders on Exchange 2010. Shared mailboxes, team calendars, and contact lists live there. Now you want to move to Exchange Online, and you don’t want to lose any of it. In this guide, we will explain how to migrate legacy public folders to Exchange Online using the manual Microsoft method. We will also look at how a professional SysInfo Exchange Server Backup Tool can help with the migration process.
Legacy Public Folders to Exchange Online Migration
Legacy public folders are shared folders that older versions of Exchange Server, like Exchange 2010, keep in a public folder database. Exchange Online works differently. It stores public folders in special public folder mailboxes, not in a database. Because of this, you can’t just move legacy folders across as they are. They have to be migrated on their own, separate from user mailboxes, when you shift to Microsoft 365. A public folder can hold many types of business data, such as:
- Shared emails
- Calendars
- Contacts
- Documents
- Team information
- Department records
- Company announcements
Methods to Migrate Legacy Public Folders to Exchange Online
|
Method |
Best for |
Main drawback |
|
Batch migration (PowerShell) |
Most organizations Many manual steps |
One batch only |
|
Outlook PST export |
Very small folders |
Microsoft recommends against it for migrating public folders |
|
SysInfoTools |
Folder-level control, easier setup |
Paid software (Free version available) |
Migrate Legacy Public Folders to Microsoft 365 Using PowerShell
You can migrate legacy public folders using Exchange Management Shell and Exchange Online PowerShell. Before starting, take a backup and check your folders, permissions, and data.
Step 01: Check Public Folders
Run these commands on your Exchange server to export folder and permission details:
Get-PublicFolder -Recurse | Export-Csv C:\PFMigration\Folders.csv
Get-PublicFolderStatistics | Export-Csv C:\PFMigration\Stats.csv
Get-PublicFolder -Recurse | Get-PublicFolderClientPermission |
Export-Csv C:\PFMigration\Permissions.csv
Step 02: Prepare the Migration Files
Download Microsoft’s public folder migration scripts. Use the scripts to export public folder statistics and create the folder-to-mailbox mapping file.
Step 03: Prepare Exchange Online
Connect to Exchange Online PowerShell and prepare the public folder mailboxes required for the migration. Connect-ExchangeOnline. Check whether any public folder mailboxes already exist: Get-Mailbox -PublicFolder
Step 04: Start the Migration
Create a migration endpoint and migration batch using the mapping CSV file. Then start the batch and monitor its status. Get-MigrationBatch. Fix any errors before moving to the final step.
Step 05: Complete the Migration
When the initial synchronization is complete, stop changes to the old public folders and complete the migration batch: Complete-MigrationBatch -Identity “LegacyPFMigration”
Step 06: Check the Migrated Data
After the migration, check the folder structure, emails, calendars, contacts, and permissions. Ask users to test their public folders before removing the old Exchange environment.
Limitations of Manual Legacy Public Folders to Exchange Online Migration
- Requires Exchange administration knowledge.
- PowerShell commands can vary by Exchange version.
- Large public folder environments require careful planning.
- Permission and mail-enabled folder issues may require additional troubleshooting.
- Migration errors can take time to diagnose.
- Incorrect preparation can affect the migration.
Professional Tool to Migrate Legacy Public Folders to Exchange Online
For a bulk migration, use the reliable SysInfo Office 365 to PST Export Tool. It allows users to migrate Public folders into Exchange Online or PST format. This tool provides a secure authentication method and offers several features, such as Preview, Remove Duplicate, Date Filter, and more. Available for both tech and non-tech users. With this tool, you can also migrate Archive Mailbox to Office 365 without any data loss.
Steps to Transfer Legacy Public Folders to Exchange Online
- Download the tool, choose Office 365, and enter its credentials to authenticate.
- Select the Backup option (Public Folder), user mapping, and the mailbox folder to migrate.
- Click on Microsoft 365 as the Destination option, apply filters, and press Start Export.
Note: For detailed steps, check the software guide for the Office 365 to Office 365 Backup Tool. Also, you can monitor the live progress report and view backup reports. If you have any queries related to this tool, contact our technical support.
Conclusion
In this technical blog post, we explored several methods to migrate legacy public folders to Exchange Online. Administrators need to review the existing folders, check permissions, clean up unnecessary data, prepare the required migration files, synchronize the data, and verify the results. For smaller environments, Microsoft’s native migration process may be enough. For large or complicated environments, a professional migration solution can help reduce manual work and provide better monitoring.
Frequently Asked Questions
Q1. Is it possible to transfer legacy public folders to Exchange Online without losing data?
Ans. Yes. You can migrate legacy public folders to Exchange Online using Microsoft’s supported migration process. Before starting, back up the data and check the migrated folders, emails, calendars, contacts, and permissions after the migration.
Q2. How will I move my archive mailbox greater than 100GB to Exchange Online?
Ans. Microsoft provides several options for archive mailbox migration; alternatively, a SysInfo Export Office 365 to PST Tool could be considered. It depends on the mailbox, Exchange version, and Microsoft 365 configuration.
Q3. Does the migration preserve the public folder hierarchy?
Ans. Yes. The migration process can transfer the existing public folder structure to Exchange Online. After migration, check the folder hierarchy to make sure everything is in the correct place.
Q4. Are public folder permissions transferred during migration?
Ans. Public folder permissions can be migrated, but they should be checked after the migration. Compare the destination permissions with the original settings to make sure users have the required access.
Q5. Can legacy public folder migration be performed in batches?
Ans. Yes. Microsoft provides a batch migration process for legacy public folders. However, only one public folder migration batch can be active at a time.
Q6. How can administrators reduce downtime during public folder migration?
Ans. Administrators can reduce downtime by preparing the source environment in advance, completing the initial synchronization before the final cutover, and scheduling the final migration during a low-usage period.
Q7. Is a pilot migration useful for legacy public folders?
Ans. Yes. A pilot migration helps administrators test the folder structure, permissions, data, and user access before moving the complete public folder environment.
Q8. Can duplicate items occur during public folder migration?
Ans. Duplicates can occur because of migration issues, repeated transfers, or problems in the source data. Check the source data and migration reports and verify the destination after migration.
Q9. What is the best software to migrate legacy public folders to Exchange Online?
Ans. The suitable software will depend on the version of Exchange you have, the size of your public folder, and your migration needs. Professional migration software will make the task easier and include functions such as filtering, mapping, progress tracking, and reporting.
Q10. How long does a legacy public folder migration take?
Ans. The time taken to migrate depends on the size of the Public Folder Data, the number of Folders and Items, the network speed, and the source Exchange environment. Large migration projects will take much more time compared to small migrations.
About The Author:
Simran Bhatia is a technical content writer engaged in writing clear, concise, and SEO-optimized content. With a background in computer science and a passion for writing, I thrive to deliver complex technical content in simple layman terms.
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