In a hybrid implementation, your public folders can reside in either on-premises Exchange or Exchange Online, accommodating users in either location. In your on-premises Exchange Server setup, there might be instances where online users need access to public files.

When you deploy the hybrid Exchange Server, you get the following benefits:

  • The mail routing between on-premises Exchange Server and Office 365 becomes secure.
  • Both platforms can share the same domain namespace for mail routing.
  • There will be a common GAL called a ‘shared address book.’
  • Calendar sharing and Free/busy between on-premises and online deployments.
  • You can easily configure the incoming and outgoing mail flow to the Exchange Online via on-premises Exchange Server.
  • A common Outlook on the web URL for both the platforms.
  • Smooth movement of on-premises mailbox messages to Exchange Online or vice-versa.
  • Centralized management of mailboxes using the Exchange Admin Center.
  • Multi-mailbox search between both platforms.
  • You can archive the on-premises Exchange messages to the cloud.

Create a public folder in hybrid Office 365 (Exchange Online)

In a hybrid environment, Public folders may exist on a single platform, either on-premises or in Exchange Online. Therefore, if you intend to create a public folder in Exchange Online (Office 365), you must meet certain requirements: -

  • Always use the Hybrid configuration wizard to sync and configure the on-premises and Exchange Online environments.
  • Make sure to enable the Outlook anywhere and functional at the on-premises Exchange Server.
  • Upgrade your Exchange Online platform to the latest version which supports the Public Folder.
  • The user should be a member of the Organization Management role group.
  • Upgrade your Outlook version to the latest which support public folders.
Start the procedure

Once you have completed all the necessary preparations, proceed with creating the public folder. However, attempting to manually create the public folder may result in an error.

The Public Folder mailbox has been automatically placed on hold for migration due to your organization's public folder deployment type being set as 'Remote.' During this migration process, users will not have access to local public folder mailboxes until the migration is successfully completed.

This error arises because Office 365 has configured the public folder as 'Remote,' allowing it to remain accessible on the on-premises Exchange Server as well.

If you do not want to face the error, then you can follow the upcoming Steps -

Step 1 - Check the root public folder mailbox using the cmdlet at the Exchange Management Shell.

(Get-OrganizationConfig) .rootpublicfoldermailbox | fl

The status of the public folders can be checked here. If the root folder is marked as 'locked' for migration, it means that the remaining public folders will also be inaccessible.

Step 2 - Check the organization configuration with the following cmdlet.

Get-OrganizationConfig | foldername *public*

If the status of the PublicFoldersEnabled attribute is marked as "remote," it indicates that Office 365 (Exchange Online) users can access the on-premises public folder.

Step 3 - Now, you need to create public folders at Office 365. First, remove all the existing public folder mailboxes from Office 365.

Get-Mailbox -PublicFolder | Remove-Mailbox -PublicFolder

NOTE - You need to run the cmdlet twice because if there are multiple public folders, then the primary mailbox will not get deleted at once.

Step 4 - After deleting the public folder mailboxes, change the configuration setting of an organization so that you can use the Public Folders at Office 365.

Set-OrganizationConfig -PublicFoldersEnabled Local -RemotePublicFolderMailboxes $null

Step 5 - Now, you can create the Public Folder in Office 365 manually by using the following Steps -

  • Login to Office 365 using the Administrator credentials. Follow Admin > Exchange > Public Folder.
  • Create a public folder mailbox. Click on Public Folder and create a public folder; then go to (•••) More option and select Root Permissions. Select the Admin as the owner.
  • Now go to the Outlook profile of the account and check if the newly created Public Folder is present there.

So, this is the whole process of creating the public folder in Office 365 (Exchange Online) in a hybrid mode.


Public Folders serve as a crucial link for hybrid Exchange Servers, enabling data accessibility across platforms. Given their significance in business operations, safeguarding them from both external and internal threats is paramount. Kernel Office 365 Backup software offers a reliable solution, allowing exclusive backup of unlimited public folders in various formats, including PST.