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Migration Manager for Exchange 8.14 - User Guide

Pre-Migration Activities Migration Process Calendar Synchronization Mailbox Migration Public Folder Synchronization Free/Busy Synchronization Tracking the Migration Progress Creating Batches of Synchronization Jobs Outlook Profile Update Fine-Tuning the Agents Using Agent Hosts for Migration Agents Configuring Migration Using PowerShell Appendix A. Measurement of Migration Agent for Exchange Performance Appendix B. Migrating Large Public Folders to Exchange 2013 (or Higher) and Office 365

Exchange 2013/2016/2019 Considerations

When migrating mailboxes to Exchange Server 2013/2016/2019, consider the following:

  • Migration Agent for Exchange cannot process a message that is larger than 40MB. This limit is set in Migration Manager for Exchange configuration project to ensure migration stability. If you have strong reasons to change that value, see the SizeLimitInMbPerBatchUploadToO365 and SizeLimitInMbPerBatchUploadToExchange parameters in Configuring Migration Using PowerShell
  • If you want to change an agent instance for a collection that is being processed, you should stop the agent, wait until the current session is finished and then specify the agent instance you need.
  • If a mailbox is added to more than one collection via groups or organizational units, the Migration Agent for Exchange processes this mailbox only for the collection that is the first in the synchronization order.
  • One instance of Migration Agent for Exchange cannot process collections from on-premise Exchange migration and Microsoft Office 365 migration projects at the same time.
  • If a mailbox move request completes with an error, delete this request before the agent creates a new one.

Mailbox Migration

Mailbox migration to the target environment is transparent. It is recommended to start mailbox migration after the domain and directory migration is completed and after the public folder data is copied to the target environment.

Calendar and free/busy synchronization should be started simultaneously with mailbox migration to enable users to work without interruption during the coexistence period.

NOTE: The scenario involving migrating users from Active Directory to Microsoft Office 365 and their mailboxes from the on-premises Exchange organization to Microsoft Exchange Online is described separately in the Migrating To Microsoft Office 365 document included in the Migration Manager documentation set.

To begin mailbox migration, right-click the Mailbox Synchronization node in the management tree and click Add Mailbox Synchronization Job. This opens a dialog box that lets you select one of the following methods to synchronize mailboxes:

  • Mailbox synchronization job
  • Office 365 Mailbox Migration Job
  • Native Move Job
  • Legacy Mailbox Synchronization Job

The guidelines for choosing the right type of job are in the Mailbox Migration Process topic.

NOTE: Office 365 mailbox migration is described in the dedicated Migrating to Microsoft Office 365 document.

You can track the mailbox migration progress using the Statistics dashboard. For information on how to do that, see Tracking the Migration Progress.

Setting Up a New Mailbox Synchronization Job

A mailbox synchronization job is currently the only method for migrating mailboxes to Microsoft Exchange 2010 (only for migration from Exchange 2010 or later by MAgE), Exchange 2013 or higher.

Step 1. Select the Source Exchange Organization

Specify the source organization where the mailboxes need to be synchronized and the credentials to use for performing the synchronization operations. You can specify a single set of credentials for working with both Active Directory and Exchange, or two distinct sets of credentials.

Step 2. Select the Target Exchange Organization

Specify the target Exchange organization where the mailboxes need to be synchronized and the credentials to use for performing the synchronization operations. You can specify a single set of credentials for working with both Active Directory and Exchange, or two distinct sets of credentials.

Step 3. Configure the Notification Message

Specify the notification messages that will be sent to the old and new mailboxes involved in the migration. Use the default notification messages or customize them as necessary.

Step 4. Set Up Migration Agent for Exchange

The Migration Agent for Exchange is used for performing direct mailbox synchronization operations. This step lets you set up the agent on an agent host that you select.

The default installation path is in the hierarchy of the Program Files system folder. You can customize the path, but your custom path will be used only if there are no previously installed instances of the Migration Agent for Exchange on the computer. Otherwise, the agent will be installed to the same location as the other existing instances regardless of the path you specify.

You can also override the default credentials that the agent will use. However, note that in this case you will be changing the credentials not only for the agent instance you are installing, but also for any existing agent instances on the agent host.

Reconfiguring Mailbox Synchronization Jobs

To change the original settings you specified during mailbox synchronization job creation, open the properties of the job.

Adding a Mailbox Collection

To create a new mailbox collection for an existing mailbox synchronization job, right-click the job in the management tree and click Add Collection.

This will start the Add Mailbox Collection Wizard, which will help you to set up and configure a new collection for the mailbox synchronization job. Each step of the wizard is described below.

Step 1. General Options

Specify the following general options:

  • The name of the mailbox collection
  • Optionally, a text description
  • Whether the collection will be enabled immediately after creation
  • The instance of the Migration Agent for Exchange that will process this collection

Step 2. Select Mailbox Database

Here, you can explicitly specify the target mailbox database where you want this collection's mailboxes to reside.

Select one of the following:

  • Move them to this mailbox database
    Select this option to explicitly specify the mailbox database to which existing mailboxes will be moved from any mailbox database that they are currently in.
  • Leave them in their current mailbox database
    Select this option if you have no mailbox database preferences. Also use it if you have already rearranged mailboxes in the target organization's mailbox databases prior to the migration and you want to keep your configuration.

Step 3. Workflow

When processing the collection Migration Manager will attempt to follow the schedule you specify on this page. By default, the option to Start as soon as possible is selected. Change this if you want to specify a date when the collection processing should be started.

Do one of the following:

  • Select Start as soon as possible to make Migration Manager start moving the mailboxes in this collection immediately.
  • Select Do not start before to make Migration Manager start processing the collection no sooner than the specified date, but this might not be the first collection in the queue.

Step 4. Collection Items

The collection can be populated with user accounts, groups and organizational units. To change the item list, use the buttons next to it.

NOTE: Migration Manager for Exchange does not process groups nested in organizational units (OUs).

Step 5. Configure Mailbox Switching

The final step in mailbox migration is to switch to the target mailbox, making it the primary mailbox for the user. You can select to perform this step automatically and specify a schedule for it.

However, you may want to defer this step in case there are problems and perform the switch manually when you have made sure the mailboxes are ready.

You can also select to skip automatic switching for mailboxes with corrupted messages and set a threshold value for the number of corrupted messages. This allows you to manually investigate such mailboxes to make sure nothing of value is lost, and later complete their migration manually.

Reconfiguring Mailbox Collections

To change the original settings you specified during mailbox collection creation, open the properties of the collection.

Skipping Messages

After you created collection, you can configure filter settings that let you exclude from migration certain message classes and/or messages that are older than a specified number of days. For that, open Properties of the collection, select the Filters node in the dialog box that appears, and specify message classes to be excluded from the migration scope.

You have two options to exclude specific message class from the scope:

  • Skip messages older than
    If this option is selected, Migration Agent for Exchange will skip all specified message classes or certain message classes of messages that are older than a specified number of days.
  • Skip all messages of the following classes
    If this option is selected, Migration Agent for Exchange will skip all specified message classes or certain message classes of messages regardless of their age.

Caution: Use separate line for every message class.

Use the following syntax for message classes:

  1. IPM.Post.*
    Skips all messages of the IPM.Post type and its subtypes.
  2. IPM.Note.Shortcut
    Skips all messages of the IPM.Note.Shortcut type.
  3. IPM.*.EnterpriseVault.Shortcut
    Skips all messages which type has the IPM prefix and the EnterpriseVault.Shortcut suffix.


  • You can use an asterisk wildcard character in names of message classes.
  • For the list of basic message classes, see the Item Types and Message Classes article. You may also use third party tools to specific determine message classes.

When specifying filters for a collection, consider the following:

  • Specified filter settings apply only starting with the next synchronization session.
  • If migration scope enlarges, messages that were previously skipped and now are included in the migration scope will not be migrated unless they are modified or you perform a full resynchronization for the mailbox.
  • To apply filters for already migrated items you need to perform resynchronization of the mailbox. Note that messages filtered out at source will be deleted from the target mailbox.

Manually Switching Mailboxes and Undoing Mailbox Switch

  1. Select the node of the mailbox collection you need.
  2. In the right pane, go to the Statistics tab.
  3. Select the mailboxes you need in the table at the bottom
  4. The Actions pane shows either the Switch or the Undo Switch action, depending on the state of the mailboxes. Click the action to perform the operation.

NOTE: After mailbox is switched, Migration Agent for Exchange continues synchronizing mail data from the source to the target mailbox to ensure that the most recent messages are successfully migrated to the target mailbox. Therefore, before removing mailbox from the collection after switch, check that mailbox was not processed during last migration session according to its Last Processed Time value.

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