Public Folder Migration Guide From On-Premises Exchange 2007+ to Office 365


This is the complete onboarding task flow for migrating Public Folders from On-Premises Exchange 2007 or later, to Public Folders on Office 365.

We recommend reading through the complete guide before starting the migration. Complete each step in the order listed. If additional instructions are required, a link to a corresponding Knowledge Base article is provided.

To see what items are included in the migration, see Which Items Are Migrated by MigrationWiz?

MigrationWiz is not a sync tool. Already migrated items updated at the source mid-migration will not be updated at the destination.

MigrationWiz does not migrate SMTP addresses for mail-enabled Public Folders. They can be exported and imported using the scripts supplied here: Migrating mail-enabled Public Folder email addresses.

MigrationWiz supports the capability to share migration projects across a Workgroup. When the Project Sharing feature is turned on, all Agents besides those who are Inactive can view all migration projects. For more information, visit Project Sharing in MigrationWiz.

MigrationWiz does not support migrating public folder permissions for Exchange 2007. Only permissions for Exchange 2010+ are migrated.

We are not able to support migrations with two-factor or multifactor authentication. 


Prepare Destination Environment

  1. This guide presumes that your Office 365 tenant and users have already been created and licenses have been assigned to those users. For instructions on setting up accounts and assigning licenses, see one of the articles below:
  2. The destination administrator account must have a valid Office 365 license assigned and an active mailbox in the Office 365 environment.
  3. Create the primary hierarchy Public Folder mailbox and assign the administrator account owner permissions at the root of the Public Folder hierarchy. For more information, see Create a Public Folder Mailbox here: Office 365 Public Folder Migration FAQ


Prepare Source Environment

  1. Grant elevated 'Organization Management' administrator role to the migrating administrator account. Refer to How do I assign the elevated admin role 'Organization Management' to the account that is performing a Public Folder migration?
  2. Ensure that the source administrator account has a mailbox enabled and is located on the same Exchange server as the source Public Folder database or mailbox.
  3. Ensure that the migrating administrator account has permission in all Public Folders (Read only or "Reviewer" access rights should be enough). For more information, see How do I ensure the admin account being used for Public Folder migration has permissions on all Public Folders?
  4. Split up large Public Folders: if any Public Folders contain more than 20,000 items (if Source = Exchange 2007), or 100,000 items (if Source = Exchange 2010 or later), these should be split into multiple Public Folders. This will speed up your migration. For more information, see How do I find the size of Source Public Folders? 
  5. Any individual Public Folders that are over 20GB in size should be split up into smaller folders of 20GB or less. Failure to complete this step can negatively impact migration performance and speed.


MigrationWiz Steps

  1. Set up the Public Folder migration project. Read the How do I create a new migration project? article for more information.
  2. Create the source and destination Endpoints (select Exchange Server Public Folder for the source Endpoint and Office 365 Public Folder for the destination Endpoint). Notes: If your Destination endpoint is with GoDaddy Office 365, then select Office 365 Public Folder for that endpoint. If your Destination endpoint is GCC High, then select Office 365 Public Folders (US Government) for that endpoint. 
  3. Add Public Folders (select Add > Quick Add and enter a forward slash ( / ) in the Root Folder Path field.) We recommend this because it will migrate all Public Folders, and you will only need one Public Folder license per 10GB of data, regardless of the number of top-level Public Folders. Refer to How do I select to migrate all my Public Folders from the root level down?
    Note: If targeting specific source folders for migration, contact Support to add those specific folders to the project instead of the top-level Root folder.
  4. Run Verify Credentials. See How do I verify credentials? (Your migration project should be created and a successful Verify Credentials completed before moving on to the next steps).
  5. If migrating more than 1000 folders, you will need to work with BitTitan Support to split the migration up so that the project runs more efficiently.
    • First step: run this PowerShell command against your source environment:
      Get-PublicFolder -Recurse -Resultsize Unlimited | select Identity | Export-Csv -Encoding Unicode C:\folders.csv
    • This will generate a file called folders.csv. Once you have that CSV, follow these steps:
      • Open the CSV and remove the names of any folders that will not be included in the migration. After you have confirmed the folders listed in the folders.csv file are the ones to be migrated, attach the file to the ticket and indicate this step has been completed. Only folders included in the CSV will be included in the migration. Any new folders created after the Public Folder Split is initiated will not be included in the scope for the migration. For suggestions on working within this restriction, see Best Practices for migrating Public Folders.
      • If you are migrating more than 20GB, stop here and contact BitTitan Support.
        • When migrating more than 20GB of data, scripts will need to be created for the project by BitTitan Support to avoid the automatic Office 365 auto-split process for Public Folder Mailboxes. For more information, see How do I migrate more than 20GB of Public folder data to Office 365? If the total size of the migration is less than 20GB, these scripts are not required.
        • Open a ticket with BitTitan Support by following the instructions in How do I get support for your products?
          • If you already have a ticket open with BitTitan Support, this information can be added to the open ticket. The subject of the ticket should be “Public Folder Split and Foldermapping”
          • Once the MigrationWiz split process is complete, a new project will be created with “_SPLIT” in the title. You must run the migration from the new project.
        • After the Public Folder mappings scripts supplied by BitTitan support have been successfully run against the Office 365 tenant, we highly recommend performing the steps outlined under Office 365 as the destination in Best Practices for migrating Public Folders.
  6. Purchase Public Folder licenses. To obtain an estimate of the number of Public Folder migration licenses required for your migration project, follow the directions in How do I estimate the number of Public Folder migration licenses required?
  7. Perform the steps outlined under Office 365 as the destination in Best Practices for migrating Public Folders.
  8. Set Project Advanced Options.
    • Under Source/Destination, set the value for Migrate Permissions For from New Folders Only to New folders and existing folders. This is required because Public Folder mapping scripts have been created. See How do I migrate Public Folder permissions?
    • Set value for Licensing/Maximum licenses to consume per item per pass licensing count. Default = 1. This allows up to 10GB to be migrated. Example: If migrating all Public Folders, using the forward slash ( / ), and the total data size = 78GB, then increase this value to 8 (otherwise the migration will pause at 10GB). See How do I enable consumption of multiple licenses for a single item?
    • Set your Preferred BitTitan Data Center. For fastest migration speeds, select the Data Center that is closest to your Office 365 destination tenant. Refer to How do I specify the data center to use for my migration?
    • Under Support Options add:
  9. Set first pass Project Advanced Options (this is to be considered your pre-stage pass).
    • Under Support Options add:
      • MaintainWatermarkCompletionState=1
    • Set Date Filter to migrate items older than six (6) months. For more information see How do I set a Date Range filter?
  10. Perform first pass for items older than 6 months by running a full migration pass.
  11. Set second pass Project Advanced Options.
    • Under Support Options:
      • Remove MaintainWatermarkCompletionState=1
      • Add SkipImportFolderWhenPublicFolderExists=1
    • Set the Date Filter to migrate items newer than six (6) months. 
  12. Perform a second pass for items newer than 6 months by running a full migration pass.
  13. Set Advanced Options for Security Group Permissions Pass. (This step can be skipped if you your source is Exchange 2007 as permissions are not supported.)
    • Under Support Options:
      • Remove SkipImportFolderWhenPublicFolderExists=1
      • Add AllowAllMailboxTypesForPFPermissions=1
  14. Perform a Security Group Permissions pass by running a full migration pass. If you do not run this pass, none of the Security Group Permissions will migrate. For more information on Security Group permissions, see How do I allow Security Groups to be migrated during a Public Folder migration project?
  15. After the migrated Public Folders have been mail-enabled in Office 365, you can use the scripts supplied here to export and import the SMTP addresses for them: Migrating mail-enabled Public Folder email addresses.
  16. If the mail-enabled Public Folders need to accept mail from external domains, you will need to run the following PowerShell command against the destination tenant. 
    Get-PublicFolder -Recurse -ResultSize Unlimited | ? {$_.MailEnabled -eq $True} | Add-PublicFolderClientPermission -User Anonymous -AccessRights CreateItems
  17. Change your primary domain type in Office 365 from Authoritative to Internal Relay for domains being used in mail-enabled Public Folder SMTP addresses. Without setting this, Office 365 bounces the message before it even checks whether a valid Public Folder address exists.
  18. Request the migration statistics. Click the bar chart icon on the MigrationWiz dashboard to receive an email containing all the project migration statistics. 
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