Exchange Public Folder Migration to Exchange Online (Microsoft 365) Cloud Migration

In this article, we will be discussing how to migrate local Exchange Server Public Folders to Exchange Online Public Folders. We will be explaining two native methods that you can use and a specialized Exchange migration tool that can make the public folder migration to Microsoft 365 smoother and simple.

Pre-Migration Planning

You should plan the migration well and also do some spring cleaning so that you would only transfer relevant data. You should also take stock of all the public folders, their size, and hierarchy.

Before the migration, you should remove obsolete and orphaned public folders. You should also consolidate oversized folders and ensure that the folders do not exceed the 10 GB size. You should also check and validate that there are no public folders which are mail-enabled without a valid SMTP address.

Moreover, you must ensure that the Exchange Server hybrid configuration is working and functioning well. This includes the following:

• No issues on the hybrid configuration wizard.
• Entra Connect is synchronized and there are no issues.
• Proper mail flow is present between the local Exchange Server and Exchange Online.

Methods to Migrate Exchange Public Folder to Exchange Online (Microsoft 365)

You can use the following native methods to migrate public folders.

1. Using Microsoft Outlook

There is the option to use Microsoft Outlook to transfer a local Exchange public folder to a cloud public folder. But it is only recommended for item migration or very small public folders. The process is not reliable and there is no continuation in case it is interrupted.

2. Using the Microsoft Migration Scripts

To migrate a public folder from local Exchange Server, there isn’t a straight forward method. Various scripting files are needed. You can follow the below stepwise procedure to migrate public folders using the Microsoft scripts.

Step 1 – Download the Scripts

First, you need to download the migration scripts from the Microsoft site. These scripts will allow you to prepare and start the migration batches. You can download and extract the files in a specific folder.

Step 2 – Generate the Statistics

To get the information about the local Exchange Server public folders and to validate the folder structure, you can run the below scripts.

Export-PublicFolderStatistics.ps1
Export-PublicFolderTree.ps1
Export-PublicFolderPermissions.ps1

Step 3 – Create Public Folders in Office 365

Using the results from the scripts (in step 2), you can create the public folders needed for the migration. Here’s how to create the public folders.

New-Mailbox -PublicFolder -Name “<public-folder-name>”

Step 4 – Starting the Migration Request

From the scripts results, you will get the necessary data and information for the migration batch to be created. Below is an example of the migration batch creation using the Public Folder Mapping from the script’s output.

New-MigrationBatch -Name PFMigration -SourcePublicFolderDatabase (Get-PublicFolderDatabase) -CSVData (Get-Content <public-folder-mapping-csv> -Encoding Byte)

To monitor the migration batches, you can use the below commands:

Get-MigrationBatch
Get-MigrationUser

Step 5 – Lock Local Public Folders

Once the first synchronization is complete, you should lock the local Exchange Public Folders so that the final sync can take place. Use the below command:

Set-OrganizationConfig -PublicFoldersLockedForMigration:$true

Step 6 – Complete the Migration

Once the local public folders are locked, the next step is to complete the last sync. Use the below command:

Complete-MigrationBatch PFMigration

Step 7 – Unlock and Use the Exchange Online Public Folders

Now, run the below command to unlock the remote folders so that the users can use the public folders.

Set-OrganizationConfig -PublicFoldersEnabled Remote

Common Issues when Migrating Public Folders

Here are some challenges and issues that you may encounter when migrating public folders using the native methods:

• When using the scripts, there is little filtering or granularity.
• Folders larger than 10 GB would cause migration failure.
• Legacy public folders might contain inconsistencies or orphaned folders can put the migration to a halt.
• There could be issue with the network that could result in slow migration performance.

An Alternative Method – Use Specialized Exchange Migration Tools

To overcome the challenges associated with the native methods, you can use specialized Exchange migration tools, such as Stellar Migrator for Exchange. This tool allows direct migration of public folders to Office 365 with granularity. Additionally, it can migrate user mailboxes and shared mailboxes across Exchange Servers and Office 365 tenants. The tool provides features such as automatic source to destination matching, incremental (delta) migration for seeding the data, and real-time/post migration reporting. This will reduce the impact on the administrators, ease up the migration effort, and guarantee success. The tool can also be used to migrate from an Exchange Server to another, Office 365 tenant to tenant, and from Office 365 to a local Exchange Server.

Conclusion

Above, we have discussed different methods for the migration of Exchange public folders to Microsoft 365. To ensure smooth and seamless migration with minimal impact and with complete data integrity, you can use a specialized Exchange migration tool, such as Stellar Migrator for Exchange. It can directly migrate public folders, shared mailboxes, and user mailboxes from local Exchange to Microsoft 365 and vice-versa, from one local Exchange to another, and from a Microsoft 365 tenant to another.