Migration to Office 365 Part4: Staged Migration of Mailboxes to Office365

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 Migrating mail boxes to office365

Ways to migrate mail box from exchange or other systems to Office365

  • Migrate all mailboxes at once (cutover migration)  

Use this type of migration if you’re running Exchange 2003, Exchange 2007, Exchange 2010, or Exchange 2013, and if there are fewer than 2000 mailboxes

  • Migrate mailboxes in batches (staged migration)   

Use this type of migration if you’re running Exchange 2003 or Exchange 2007, and there are more than 2,000 mailboxes.

  • Migrate using an integrated Exchange Server and Office 365 environment (hybrid) 

Use this type of migration to maintain both on-premises and online mailboxes for your organization and to gradually migrate users and email to Office 365. Use this type of migration if:

    • You have Exchange 2010 and more than 150-2,000 mailboxes.

    • You have Exchange 2010 and want to migrate mailboxes in small batches over time.

    • You have Exchange 2013.


·        Use Office 365 Import Service to migrate PST-files

  • Migrate email from another IMAP-enabled email system

You can use the Internet Message Access Protocol (IMAP) to migrate user email from Gmail, Exchange, and other email systems that support IMAP migration. When you migrate the user’s email by using IMAP migration, only the items in the users’ inbox or other mail folders are migrated. Contacts, calendar items, and tasks can’t be migrated with IMAP, but they can be by a user.

IMAP migration also doesn’t create mailboxes in Office 365. You’ll have to create a mailbox for each user before you migrate their email.

Staged migration preparations

Configure Outlook Anywhere on your on-premises Exchange Server  

The email migration service uses Outlook Anywhere (also known as RPC over HTTP), to connect to your on-premises Exchange Server


    • Verify that you can connect to your Exchange organization using Outlook Anywhere 

    • Set permissions the on-premises user account that you use to connect to your on-premises Exchange organization (also called the migration administrator) must have the necessary permissions to access the on-premises mailboxes that you want to migrate to Office 365. This user account is used when you connect to your email system by creating a migration endpoint.

To migrate the mailboxes, the admin must have one of the following permission sets:

        Domain Admin

         FullAccess permission for each on-premises mailbox and the WriteProperty permission to modify the TargetAddress property on the on-premises user accounts.

        Receive As permission on the on-premises mailbox database that stores user mailboxes and the WriteProperty permission to modify the TargetAddress property on the on-premises user accounts.

    • Disable Unified Messaging (UM)

    • Use directory synchronization to create new users in Office 365

To enable Outlook Anywhere, follow these steps in order:

1.     Install a valid Secure Sockets Layer (SSL) certificate from a trusted certification authority (CA) that the client trusts.

2.     Install the Windows RPC over HTTP Proxy component.

3.     Enable Outlook Anywhere on a computer that has the Exchange Server 2007 Client Access server role installed.

enable-OutlookAnywhere -Server: -ExternalHostName: -ExternalAuthenticationMethod: Basic -SSLOffloading:$false

Create a CSV file for a staged migration batch

After you identify the users whose on-premises mailboxes you want to migrate to Office 365, you use a comma separated value (CSV ) file to create a migration batch. Each row in the CSV file—used by Office 365 to run the migration—contains information about an on-premises mailbox.

Supported attributes

The CSV file for a staged migration supports the following three attributes. 

 Email Address, Password, ForeceChangePassword

CSV file format




Create a migration endpoint

To migrate email successfully, Office 365 needs to connect and communicate with the source email system. To do this, Office 365 uses a migration endpoint. To create an Outlook Anywhere migration endpoint by using PowerShell, for staged migration

First connect to Exchange online

$UserCredential = Get-Credential

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection

Run Following command

$Credentials = Get-Credential

New-MigrationEndpoint -ExchangeOutlookAnywhere -Name StagedEndpoint -Autodiscover -EmailAddress administrator@contoso.com -Credentials $Credentials

Verified it worked

Get-MigrationEndpoint StagedEndpoint | Format-List EndpointType,ExchangeServer,UseAutoDiscover,Max*

Create and start a stage migration batch

You can use the New-MigrationBatch cmdlet in Exchange Online PowerShell to create a migration batch 

New-MigrationBatch -Name StagedBatch1 -SourceEndpoint StagedEndpoint -AutoStart

Verified it worked

Get-MigrationBatch -Identity StagedBatch1 | Format-List

Get-MigrationBatch -Identity StagedBatch1 | Format-List Status

Convert on-premises mailboxes to mail-enabled users

After you have successfully migrated a batch of mailboxes, you need some way to let users get to their mail. A user whose mailbox has been migrated now has both a mailbox on-premises and one in Office 365. Users who have a mailbox in Office 365 will stop receiving new mail in their on-premises mailbox.

Because you are not done with your migrations, you are not yet ready to direct all users to Office 365 for their email. So what do you do for those people who have both? What you can do is change the on-premises mailboxes that you’ve already migrated to mail-enabled users. When you change from a mailbox to a mail-enabled user, you can direct the user to Office 365 for their email instead of going to their on-premises mailbox.

Delete a staged migration batch

After all mailboxes in a migration batch have been successfully migrated, and you’ve converted the on-premises mailboxes in the batch to mail-enabled users, you’re ready to delete a staged migration batch. Be sure to verify that mail is being forwarded to the Office 365 mailboxes in the migration batch. When you delete a staged migration batch, the migration service cleans up any records related to the migration batch and deletes the migration batch.

Remove-MigrationBatch -Identity StagedBatch1

Verify it worked

            Get-MigrationBatch StagedBatch1

Assign licenses to Office 365 users

1.     Sign in to Office 365 with your work or school account as a global admin. Learn how to sign in.

2.     Select the app launcher icon in the upper-left and choose Admin.

3.     Do one of the following:

4.     In the Office 365 admin center, choose Users > Active Users.

5.     Under users & groups, choose Add users, reset passwords, and more (for Office 365 small and midsized business subscriptions that were purchased through a partner).

6.     Select the boxes for the names of the users who you want to assign or unassign licenses for.

7.     On the right, choose Edit.

8.     On the details page, choose Next.

9.     On the settings page, choose Next.

10.  On the assign licenses page, do one of the following:

a.     To assign licenses to the selected users, select Add to existing license assignments, and then select the check boxes for the licenses that you want to assign.

b.     To unassign licenses from the selected users, select Replace existing license assignments, and clear the check boxes for the licenses that you want to unassign.

11.  Choose Submit> Finish

By: www.wizsystem.co.uk

Complete post-migration tasks

Create an Autodiscover DNS record so users can easily get to their mailboxes

After all on-premises mailboxes are migrated to Office 365, you can configure an Autodiscover DNS record for your Office 365 organization to enable users to easily connect to their new Office 365 mailboxes with Outlook and mobile clients. This new Autodiscover DNS record has to use the same namespace that you’re using for your Office 365 organization. For example, if your cloud-based namespace is cloud.contoso.com, the Autodiscover DNS record you need to create is autodiscover.cloud.contoso.com.

Office 365 uses a CNAME record to implement the Autodiscover service for Outlook and mobile clients. The Autodiscover CNAME record must contain the following information:

·        Alias: autodiscover

·        Target: autodiscover.outlook.com

Decommission on-premises Exchange servers. After you’ve verified that all email is being routed directly to the Office 365 mailboxes, and you no longer need to maintain your on-premises email organization or don’t plan on implementing an SSO solution, you can uninstall Exchange from your servers and remove your on-premises Exchange organization.

You can either run Exchange 2010 Setup.exe or navigate to Control Panel to modify or remove Exchange 2010 (either server roles or an entire installation).

1.      The Maintenance Mode page of the Exchange Server 2010 Setup wizard begins the process of changing or removing your Exchange installation. Click Next to continue.

2.      On the Server Role Selection page, select the Exchange server roles that you want to add (if you’re changing an installation) or remove (if you’re removing one or more server roles or an entire installation). Click Next to continue.

3.      On the Readiness Checks page, view the status to determine if the organization and server role prerequisite checks completed successfully. If the prerequisites check doesn’t complete successfully, review the Summary page to help troubleshoot and fix any issues that are preventing Setup from completing. If the checks have completed successfully, click Install if you want to add a server role or Uninstall to remove the specified server role(s) or the entire installation of Exchange 2010.

4.      On the Completion page, click Finish.

Credit : Microsoft, exchange.org
By: www.wizsystem.co.uk

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