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Public Folder Migration Guide From On-Premises Exchange 2007+ to Hosted Exchange > 50GB

Last Update: 7/21/2017 11:32 AM
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Important: When you sign in to MigrationWiz, you are redirected to the Getting Started page in MSPComplete. To get to a migration project created before April 4, 2017, click the Go to Projects button on the Getting Started Page. To create a new project for the migration scenario documented in this article, click the waffle icon (waffle.png) in the top navigation bar of MSPComplete, and select the appropriate migration product.


  • This is the complete Onboarding Task flow for migrating Public Folders from On-Premises Exchange 2007 or later, to a multi-tenant Hosted Exchange environment.​
  • This guide should be followed if the total size of the Source Public Folders is more than 50GB. If the Source Public Folders are less than 50GB, refer to KB005129.
  • Complete each step in order. If additional instructions are required, a link to a corresponding Knowledge Base article is provided.
  • Due to a code defect in Exchange 2010, timestamps will not be preserved for Public Folders at the Destination. KB005159

Prepare Source Exchange Environment:

  • Set elevated "Organization Management" admin role to migrating admin account (this grants permission to all necessary read-only fields). KB004788
  • Ensure migrating admin account has permission on all Public Folders (owner access rights need to be permitted to the account being used for migration). KB005103
  • Split up large Public Folders. If any Public Folders contain more than 20,000 items (if the Source = Exchange 2007), or 100,000 items (if the Source = Exchange 2010 or later), these should be split into multiple Public Folders. This will speed up your migration. KB005526

Prepare Destination Hosted Exchange Environment:

  • Create a top-level Public Folder on the Destination. (Do not create subfolders. Let MigrationWiz create these during the migration, so that permissions get migrated over.)
  • Ensure that the migrating admin account has permission on all Public Folders (owner access rights need to be permitted to the account being used for migration). KB005103

    Note: You will not be able to run the PowerShell commands on your Hosted Exchange environment. Ask the Hosted Exchange provider to add this permission to the account that is being used for migration.
  • When migrating to a multi-tenant Hosted Exchange environment, the Public Folder structure on that hosted environment is under a top-level Public Folder, and not under the root folder. Additionally, the Hosted Exchange provider will not grant access to the root of their Public Folders, since this is a shared environment. Therefore, ask the provider to run the PowerShell script below so that we can obtain the unique identifier for the customer's top-level Public Folder. Then add that to the MigrationWiz project, under Advanced Options (this step is included in the MigrationWiz section below).
  • This is the PowerShell script that your Hosted Exchange provider must run in order to obtain that PublicFolderRootEntryId:

    Get-PublicFolder "\the path of the PF" | fl entryid*
    Note: Record the output of this script. This needs to be entered under the MigrationWiz project's Advanced Options (as indicated in the MigrationWiz Steps section below).

MSPComplete Steps:

  • Create a customer. KB005421
  • Create the Source and Destination endpoints (select Exchange Server Public Folder  for the source endpoint, and Office 365 for the destination endpoint). KB005427
  • Launch public folder migration (select All Products/Public Folder Migration).

MigrationWiz Steps:

  • Set up the project (create a Public Folder project/name the project and select the MSPComplete customer/select the source endpoint/select the destination endpoint).
  • Add Public Folders. To understand how pricing works, refer to KB004863.
    • Choose to migrate all Source Public Folders.
      • Select Add/Quick Add and enter a forward slash ( / ) within the field labeled Root Folder Path. KB004914
    • Use BitTitan AutoDiscover to discover all Public Folders on the Source, and then import them into your MigrationWiz dashboard. This allows you to pick and choose which Public Folders to migrate. Note: Each top-level folder will consume one Public Folder license. KB004915
      • Select Add/AutoDiscover items/Start Autodiscover/Import.
  • Set Project Advanced Options KB004834
    • Under Licensing:
      • Set value for Maximum licenses to consume per item per pass licensing count
        Default value = 1. This allows up to 10GB to be migrated. For example: If migrating all Public Folders, using a forward slash ( / ), and the total data size = 39GB, then increase this value to 4, otherwise the migration will pause at 10GB. KB004890
    • Under Performance:
      • Set Preferred BitTitan Data Center.
        For fastest migration speeds, select the Data Center that is closest to your Hosted Exchange Provider. KB004268
    • Under Support/Support Options, add:
      • RemoveFilterBasedOnFolderType=1
        This flag is required if Public Folders contain items other than mail, such as calendar and contact items. KB005053
      • PublicFolderImportRootEntryId=xxxxxxxxxxxxxxxxxxxxx
        • The name of the Advanced Option is case-sensitive, and should be entered exactly as shown above.
        • The PublicFolderImportRootEntryId option should contain the EntryId of the destination top-level Public Folder.
        • Replace the "x"s with the ID that was obtained when running the PowerShell script provided in the "Prepare Destination Hosted Exchange Environment" section of this Migration Guide.
        • After entering this text, click on the "+" sign to save the entry.
  • Run Verify Credentials. KB004511
  • If the Source Public Folders have more than 1000 folders below the top-level folder, work with BitTitan Support so that the migration can be split up, based on migration points after every 1000 folders. KB005239
    • Note: Once the tool is complete, you must run the migration from the new project, and can then delete the original project.
  • Purchase Public Folder licenses. KB004647
    • To obtain an estimate of the number of Public Folder migration licenses required for your migration project, follow the directions in KB005791.
  • Allocate Public Folders to the correct Public Folder mailboxes on Office 365, to allow the mailboxes to stay below the 50GB limit. KB004924
    • Note: This step can take several days to complete, so allow time for this in your project plan.
  • First Pass MigrationWiz Steps:
    • Set first pass Project Advanced Options: KB005067
      • Add: MaintainWatermarkCompletionState=1
      • Set date to migrate items older than six (6) months.
  • Second/Final Pass MigrationWiz Steps:
    • Set second pass Project Advanced Options: KB005067
      • Remove: MaintainWatermarkCompletionState=1
      • Add: SkipImportFolderWhenPublicFolderExists=1
      • Set the date to migrate items newer than six (6) months.
  • Perform Full Migration pass (put a checkmark in the box next to Root Path, select the Start button > select Full Migration from the drop-down list >click on the Start Migration button).
  • Perform a final Full Migration pass using the Advanced Option AllowAllMailboxTypesForPFPermissions=1 in order to migrate all Security Group Permissions. If you do not run the second pass, none of the Security Group Permissions will migrate.
  • Receive migration statistics (click on the pie chart on the MigrationWiz dashboard to receive an email containing all the project migration statistics). KB004626