Exchange Cutover Migration
Topic Last Modified: 2013-02-01
Use email migration in the Exchange Control Panel to migrate all the mailboxes and corresponding mailbox data from Exchange to your cloud-based email organization. This type of migration is called a cutover migration because all on-premises mailboxes are migrated in preparation for moving your entire email organization to the cloud.
An organization can migrate a maximum of 1,000 Exchange 2010, Exchange 2007, or Exchange 2003 mailboxes to the cloud by using a cutover Exchange migration.
- What happens during a cutover Exchange Migration
- Before you begin
- Step 1 Start a migration batch
- Step 2 Configure the connection settings
- Step 3 Run the migration batch
- Step 4 Complete the migration
- Step 5 Implement a single sign-on solution (optional)
- Step 6 Remove your on-premises Exchange organization (optional)
- Best practices
- Next steps
When you migrate Exchange mailboxes to the cloud in a cutover Exchange migration:
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The migration service provisions new mailboxes in your cloud-based organization. It creates a cloud-based mailbox for each user account in your on-premises Exchange organization. On-premises distribution groups and contacts are also migrated to the cloud.
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After the new cloud-based mailboxes are created, the migration service migrates email messages, contacts, and calendar items from the Exchange mailboxes to the corresponding cloud-based mailboxes.
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After the initial migration, the Exchange and cloud-based mailboxes are synchronized every 24 hours, so that new email sent to the Exchange mailbox is copied to the corresponding cloud-based mailbox.
When you're ready, you can route email directly to the cloud-based mailboxes, complete the migration, and then remove your on-premises Exchange organization.
Important: |
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| If you’ve activated and installed the Microsoft Online Services Windows Azure Active Directory Sync tool, you can’t run a cutover Exchange Migration. If you’ve installed the Windows Azure Active Directory Sync tool, you can deactivate directory synchronization and then run a cutover Exchange migration. For more information, see Manage directory synchronization. |
- Configure Outlook Anywhere on your on-premises Exchange server The email migration service uses RPC over HTTP, or Outlook Anywhere, to connect to your on-premises Exchange server. For information about how to set up Outlook Anywhere for Exchange 2010, Exchange 2007, or Exchange 2003, see the following:
- Exchange 2010: Enable Outlook Anywhere
- Exchange 2007: How to Enable Outlook Anywhere
- Exchange 2003: Deployment Scenarios for RPC over HTTP
- How to Configure Outlook Anywhere with Exchange 2003
- Exchange 2010: Enable Outlook Anywhere
- Verify that you can connect to your Exchange organization using Outlook Anywhere Try one of these connection methods:
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Use Microsoft Outlook from outside your corporate network to connect to Exchange.
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Use the Microsoft Exchange Remote Connectivity Analyzer (ExRCA) to test your connection settings.
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Run the following Windows PowerShell commands.
$PSCredentials = Get-Credential
Test-MigrationServerAvailability -Autodiscover -EmailAddress <migration administrator email address> -Credentials $PSCredentials
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Use Microsoft Outlook from outside your corporate network to connect to Exchange.
- Assign the migration administrator permissions to access mailboxes in your Exchange organization The on-premises account that you use to run a migration batch must have the necessary permissions to access all user mailboxes. You can assign the Full Access permission for individual mailboxes or assign the Receive As permission for a mailbox database. For more information, see the following:
Exchange 2010
Exchange 2007
Exchange 2003
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Microsoft Knowledge Base article 268754 - How to assign users or groups full access to other user mailboxes
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Microsoft Knowledge Base article 821897 - How to assign service account access to all mailboxes in Exchange Server 2003
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Microsoft Knowledge Base article 268754 - How to assign users or groups full access to other user mailboxes
- Add your Exchange organization as an accepted domain of your cloud-based email organization The migration service uses the SMTP address of your on-premises mailboxes to create the Skype ID (and email address) for the new cloud-based mailboxes. Migration will fail if your Exchange domain isn't an accepted domain (or the primary domain) of your cloud-based organization. For more information, see Create Accepted Domains.
- Disable unified messaging If the mailboxes you are migrating are enabled for unified messaging (UM), you have to disable UM on the mailboxes before you migrate them. You can then enable UM on the mailboxes after the migration is complete. For more information, see Migrate UM-Enabled Mailboxes.
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Select Manage My Organization > Users & Groups > Email Migration > New. On the Welcome to Email Migration page, select one of the following migration types:
- Exchange 2007 and later versions - Automatically detect connection settings with Autodiscover Select this option if you want the migration service to automatically connect to your on-premises Exchange server using the Autodiscover service.
- Exchange 2003 and later versions - Manually specify connection settings Select this option if your on-premises messaging system is running Exchange 2003 or if you are running a later version but want to manually provide the connection settings to your on-premises mail server.
- Exchange 2007 and later versions - Automatically detect connection settings with Autodiscover Select this option if you want the migration service to automatically connect to your on-premises Exchange server using the Autodiscover service.
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Click Next after you select a migration type.
Provide the credentials and connection settings for your on-premises Exchange server depending on the migration type that you selected. Perform only one of the following tasks based on your migration type.
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If you selected this migration type, configure the migration to use the Autodiscover service to detect the connection settings. The connection settings you configure will persist on this page the next time you start Email Migration to run a new migration batch.
In this field… Do this… * Migration administrator email address
Type the email address for an administrator account that has access to your Exchange server and all mailboxes.
* Domain\Username
Type the username for the migration administrator account. Use the Domain\Username or UPN format.
* Password
Type the password for the migration administrator account.
Number of mailboxes to migrate simultaneously
Specify the number of connections to the Exchange server available to migrate mailboxes to the cloud. If the value is set to 3, the default value, you can migrate up to three mailboxes at the same time until all the mailboxes in the migration batch have been migrated. The maximum number of connections is 10. To learn more about how to optimize this setting, see Maximum Number of Connections to Your Mail Server.
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Click Next. Microsoft Exchange tries to communicate with the on-premises Exchange server to verify the Autodiscover connection settings.
If the test connection isn't successful, you are prompted to manually specify the connection settings. You have to connect to the Exchange server to continue.
If you can’t connect to your on-premises Exchange server, see this video for troubleshooting tips.
When the test connection to the Exchange server is successful, the Start the Migration page is displayed.
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If you selected this migration type, provide the connection settings to your Exchange server.
In this field… Do this… * Domain\Username
Type the username for the migration administrator account. Use the domain\username format.
* Password
Type the password for the migration administrator account.
* Exchange server
Type the FQDN of the on-premises Exchange server. For example, EXCH-MSG-1.contoso.com.
* RPC proxy server
Type the FQDN of the RPC proxy server for the on-premises Exchange server. For example, mail.contoso.com.
Authentication
Select
Basicas the authentication method used by the Exchange server.Number of mailboxes to migrate simultaneously
Specify the number of connections to the Exchange server available to migrate email to cloud-based mailboxes. If the value is set to 3, the default value, you can migrate up to three mailboxes at the same time until all the mailboxes in the migration batch have been migrated. The maximum number of connections is 10. To learn more about how to optimize this setting, see Maximum Number of Connections to Your Mail Server.
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Click Next. Microsoft Exchange tries to communicate with the on-premises Exchange server to verify the manual connection settings. If the test connection isn't successful, you'll be asked to verify the connection settings. You have to connect to the Exchange server to continue.
If you can’t connect to your on-premises Exchange server, see this video for troubleshooting tips.
When the test connection to the Exchange server is successful, the migration service connects to the directory on the on-premises Exchange server and queries it to get a list of the mailboxes, distribution groups, and contacts that will be migrated. It might take awhile to collect this information.
When this query process is complete, the Start the Migration page is displayed.
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Decide if you want Microsoft Exchange to send a status email message to other users when the migration batch is done running. If so, click Browse to select one or more users.
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Review the number of mailboxes, distribution groups, and contacts that will be migrated.
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To start processing the migration batch, click Run.
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To cancel the current migration batch and return to step 1, click Start Over.
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To start processing the migration batch, click Run.
After you start the migration, two panes are displayed on the Email Migration tab:
- Active Email Migration This pane contains the following information about the migration batch in progress:
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The date and time when the migration batch was started, and the user who started the migration.
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The total number of items to be migrated or created. This includes mailboxes, distribution groups, and contacts that were inventoried on your on-premises Exchange server.
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The number of migration requests from the current migration batch that have been completed. This field is updated throughout the migration.
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The number of active mailbox migrations. This number corresponds to the number of simultaneous connections that you specified.
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A link to the Active Mailbox Migration report, which shows detailed information about each mailbox that is being actively migrated. A compilation of this report, which contains similar information for all the recipient types in the migration batch, is included in the status email message sent to the administrator after the migration batch is done running.
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The number of failed migrations.
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A link to the Error Report for Active Migrations that documents each migration error found during the processing of the current migration batch. For each error, the report includes a suggestion for fixing the error. Use this information to address the cause of the error, and then start a new migration batch. For more information, see Troubleshoot Active Migration Errors (EmailMigrationViewMigrationBatchErrorsLearnMore).
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The date and time when the migration batch was started, and the user who started the migration.
- Email Migration This pane contains information about the overall migration, which consists of all the Exchange migration batches that you've run. It contains the following information:
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The number of mailboxes, distribution groups, and contacts from all migration batches that have been migrated. Mailboxes are synchronized with the corresponding on-premises mailbox every 24 hours.
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The number of mailboxes that have encountered synchronization errors since the overall migration was started.
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A link to the Error Report for Synchronization Failures, which identifies synchronization failures that are preventing Microsoft Exchange from retrieving new email messages sent to a user's on-premises Exchange mailbox. For more information, see Troubleshoot Migration Subscription Failures.
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The number of mailboxes, distribution groups, and contacts from all migration batches that have been migrated. Mailboxes are synchronized with the corresponding on-premises mailbox every 24 hours.
Microsoft Exchange sends you a status email message after the migration batch is completed. This message includes the following:
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Statistics about the migration batch, which includes number of mailboxes successfully migrated and the number of distribution groups and contacts created.
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A link to the MigrationStatistics.csv file. This file contains a list of all the items that were successfully migrated. This report also contains an autogenerated, 8-character alpha-numeric password for each mailbox that was successfully migrated. Users have to use this password the first time they access their cloud-based mailbox. Users are required to reset this password when they sign in for the first time.
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A link to the MigrationErrors.csv file. This file contains information about each mailbox that failed migration.
To stop a migration batch, in the Active Email Migration pane, click Stop.
What happens when you click Stop? The migration of any mailbox currently being processed is stopped immediately and isn't completed. Stopping a migration batch won't affect mailboxes that have been migrated already.
After you stop a migration batch, you receive a status email message that says how many mailboxes were successfully migrated before the batch was stopped. This message also contains a link to the MigrationErrors.csv that identifies the active mailbox migrations that were in progress when the migration was stopped and the rows waiting to be migrated. The status message also contains a link to the MigrationStatistics.csv file that identifies the mailboxes that were successfully migrated.
If there are errors in a migration batch or if new mailboxes, contacts, or distribution groups were created in your on-premises Exchange organization, you can start a new migration batch. You don't have to enter connections when you start a new migration because they persist from the previous batch. When you start a new migration batch, the migration service connects to your on-premises Exchange server and queries the directory for new mailboxes, distribution groups, and contacts. When this query is complete, the Start the Migration page displays the number of mailboxes, distribution groups, and contacts that will be migrated in the new migration batch.
Note If you run additional migration batches, the migration service skips the mailboxes, distribution groups, and contacts in your on-premises Exchange organization that have already been migrated.
After you've run all your Exchange migration batches for your on-premises Exchange organization, you're ready to complete the migration. Follow these steps:
- Configure your MX record to point to your cloud-based email organization Until you change your MX record, email sent to users is still routed to their on-premises Exchange mailboxes. When a user mailbox is successfully migrated, the on-premises Exchange mailbox and cloud-based mailbox are synchronized once every 24 hours until you complete the overall migration. When you configure your organization's MX record to point to your cloud-based email organization, all email is sent directly to the cloud-based mailboxes.
After you change the MX record and verify that all email is being routed to the cloud-based mailboxes, you're ready to complete the migration.
Important It can take from 24 to 72 hours for the updated MX record to be propagated. Wait at least 24 hours after you change the MX record before you complete the migration. Verify that mail is being routed to cloud-based mailboxes before you complete the migration.
- Complete the overall migration process Click Complete Migration in the Email Migration pane. What happens when you click Complete Migration?
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Microsoft Exchange runs a final synchronization for all mailboxes. After this, email is no longer synchronized between the on-premises Exchange mailboxes and cloud-based mailboxes.
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Microsoft Exchange sends a final status email message after the migration is complete.
- Ignore synchronization errors The migration service ignores any final synchronization errors and completes the migration. If there are errors, the status message sent to the administrator contains a link to the MigrationErrors.csv file.
- Don't ignore synchronization errors If there are any final synchronization errors, the migration service doesn't complete the migration. Instead, it displays a link to the Error Report for Synchronization Failures. If you don't ignore synchronization errors, the migration will be completed only when there are no synchronization errors.
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Microsoft Exchange runs a final synchronization for all mailboxes. After this, email is no longer synchronized between the on-premises Exchange mailboxes and cloud-based mailboxes.
After all mailboxes are migrated to the cloud, you can implement a single sign-on solution to enable users to use their on-premises Active Directory credentials (username and password) to access their Office 365 mailboxes and existing on-premises resources. You implement a single sign-on solution by deploying Active Directory Federation Services (AD FS) 2.0 (AD FS 2.0). For more information, see Cutover Exchange Migration and Single Sign-on.
After you’ve verified that all email is being routed directly to the cloud-based mailboxes, completed the migration, and no longer need to maintain your on-premises email organization or don’t plan on implementing a single sign-on solution, you can uninstall Exchange from your servers and remove your on-premises Exchange organization. For more information, see the following:
Here are some tips to optimize your Exchange migration:
- Change the DNS Time-to-Live (TTL) setting on your MX record Before you start to migrate mailboxes, change the DNS TTL setting on your current MX record to a shorter interval, such as 3600 seconds (one hour). Then, when you change your MX record to point to your cloud-based email organization after all mailboxes are migrated, the updated MX record should propagate more quickly because of the shortened TTL interval.
- Communicate with your users Give users a heads-up that you are migrating the content of their on-premises Exchange mailboxes to your cloud-based organization. Consider the following:
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Ask users to delete old or unnecessary email messages from their Exchange mailbox before migration. This helps reduce the amount of data that has to be migrated and can help reduce the overall migration time. Or you can clean up their mailboxes yourself.
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Suggest that users to back up their Inbox.
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Tell users when they can use their cloud-based account to access the email that was migrated from their on-premises account. Don't give users access to their cloud-based accounts until you're ready to complete the migration.
Need a good way to provide users with their sign-in credentials and autogenerated password for their new cloud-based accounts? See Send a Welcome Message to New Users.
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Ask users to delete old or unnecessary email messages from their Exchange mailbox before migration. This helps reduce the amount of data that has to be migrated and can help reduce the overall migration time. Or you can clean up their mailboxes yourself.

Important: