BitTitan: Migrate Public Folders from Exchange to Microsoft 365 Using BitTitan
Assess and plan your public folder migration scope. List all the folders you want to migrate, along with the size and number of files. BitTitan Support should be contacted if you plan to migrate more that 1,000 folders including subfolders or 20GB. You can also break public folders of more 100,000 items up into multiple folders.
Verify the Exchange Web Service (EWS). EWS must be activated on both destination and source environments. Microsoft has stated that EWS blocking will begin October 1, 2026.
Prepare the Exchange environment. Grant migration administrator access at root level to all public files with at minimum read-only rights or “Reviewer”. Verify that the administrator’s account is enabled with a mailbox on the Exchange server where the source database public folders are located. For Hosted Exchange, request the provider run a PowerShell script to obtain the PublicFolderRootEntryId.
Create Microsoft 365 accounts for users with the appropriate licenses. Microsoft 365 Admin Center enables you to set up the first public mailbox (which will be the primary hierarchy mail) in your destination tenant. Assign Full Access permissions for the public-folder mailbox to the destination administrator’s account.
Set public folder quotas unlimited. Microsoft 365 has a default of 2GB and a warning when 1.7GB. That is too little for migration. You can make the changes by using PowerShell Scripts or Exchange management portal.
Pre-allocate mail folders for large data migrations. If migrating over 20GB of information, contact BitTitan Support. They will generate PowerShell Scripts that properly pre-allocate mail folders. Microsoft 365 can’t perform an auto-split which may take up to two week to complete. It will also block access to any public folders that are affected.
Create a MigrationWiz project for the public folder Login to MigrationWiz. Click on “Public Folder” and choose it as your migration type. Enter a name for the project and select your client.
Configure source-and-destination endpoints. Set up the source endpoint with your Exchange (On Premises Exchange 2007+ or Hosted Exchange) and the target endpoint with Microsoft 365 Public Folders. Fill out the client ID field and the tenant ID field for Microsoft 365 endpoints.
Add public Folders to Migration Project Enter the Public Folders to Migrate in the Root Folder Path Field. Use of a forward-slash (/), will migrate public folders all the way down to the root.
Export SMTP adresses for mail-enabled publicly folders. Run provided export scripts to create a CSV containing SMTP adresses for mail – enabled public files. MigrationWiz is unable to migrate SMTP addresses of mail-enabled private folders. You will need to export and import them separately.
Verify Credentials – Run this pass. Perform a credential verification to confirm that both the source and destination endspoints are
Configure advanced settings for migration Set any advanced options needed to meet your migration needs, including filtering by dates or items, folder mapping and any customizations.
Execute Initial Migration Pass Run the initial migration passes to transfer public data folders, permissions as well as associated data such emails, contacts and calendars from the source destination.
Run additional migrations Execute further migrations (typically 2 or 3 passes in total) so that any changes are captured and all permissions of security groups have been migrated.
Configure mail flows for mail-enabled folders. Review the configuration of mail routing and ensure that all emails sent to folders which are mail-enabled will reach their destinations. Using the provided script, import the previously export SMTP addresses.
Complete all post-migration activities. Provide users with public folders that have been migrated. Validate folder rights and communicate to them any changes. Monitor the environment source and retire once migration is complete.
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