1. Prepare for Staged Migration

This is the primary and first step that require Global Admin rights in Office 365 portal. Using office 365 portal login through Global Admin and do the following

Register the domain you configured for MS Exchange (on-Prem) 2007/2003.

It contains following 3 steps

  1. Domain On-line Verification.
  2. Creating online users or leaving it for later attempt if SEM is the process.
  3. Domain confirmation with services to use license. After successful completion of this step you have added an Accepted Domain in Exchange Online.

    Important: make that domain default if that is your on-prem messaging domain.

  4. Initiate Windows Azure Active Directory Synchronization.
  5. Download latest DirSyncTool from the site.
  6. Create a user (service Account) for Dir-Syncing and assign permission of EntAdmin, SchemaAdmin(optional) etc.
  7. Add that created Admin user to the local Admin group of the computer where you are going to install DirSyncTool.
  8. Install it on a separate server that is prepared for DirSyncTool located on prem with Admin Privillages.
  9. Now, during configuration of DirSyncTool provide Admin user credentials for both of the sides (On-prem and Office 365).
  10. Test Microsoft Outlook Anywhere whether its functional or not using Remote Exchange Connectivity Analyzer.
  11. 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 and modify the on-premises mailboxes that you want to migrate to Exchange Online. This user account is used to create a migration endpoint to your on-premises organization.


Either of the Following permission must be granted to migration administrator user

  1. Domain Admins group in Active Directory in the on-premises organization.
  2. FullAccess permission for each on-premises mailbox AND the WriteProperty permission to modify the TargetAddress property on the on-premises user account.
  3. Receive As permission on the on-premises mailbox database that stores the user mailboxes AND the WriteProperty permission to modify the TargetAddress property on the on-premises user account.

2. CSV

Create a CSV with the following compulsory attributes (3 attributes are compulsory).

  1. Email Address
  2. Password
  3. ForcePasswordChange

It’s example is given below


Note: before uploading CSV, it is important to create Endpoint on Exchange online or you can create these endpoints later after uploading CSV.

Create Staged Migration Batch

To create a migration batch, you have to submit a CSV file that contains the information about the mailboxes you want to migrate. You can create and start a maximum of 100 migration batches at a time.

  1. In the EAC, navigate to Recipients > Migration.
  2. Click New Add Icon and then click Migrate to Exchange Online.
  3. On the Select a migration type page, click Staged migration, and then click Next.
  4. On the Select the users page, click Browse to specify the CSV file to use for this migration batch.

After you select a CSV file, Exchange Online checks the CSV file to make sure that:

  1. It isn't empty.
  2. It uses comma-separated formatting.
  3. It doesn't contain more than 2,000 rows.
  4. It includes the required EmailAddress column in the header row.
  5. It contains rows with the same number of columns as the header row.
    1. If any one of these checks fails, you'll get an error that describes the reason for the failure.
    2. Click Next.
  6. Depending on whether any Outlook Anywhere migration endpoints have been created for your Exchange Online organization, do one of the following.

    No migration endpoints have been created: On the Enter on-premises account credentials page, type the user name and password for an account that has the necessary administrative privileges in the on-premises Exchange organization that hosts the mailboxes you're migrating. Use the domain\user name format for the name of the administrator account. Click Next. Exchange Online will use the email address of the user in the first row of the CSV file, the administrative account, and the Autodiscover service to detect the connection settings to your on-premises Exchange organization. If the connection settings are successfully discovered, the fully qualified domain name (FQDN) of your on-premises Exchange server and RPC proxy server are displayed on the Confirm the migration endpoint page. Verify the settings and then click Next. If the test connection to the source server isn't successful, you’re prompted to manually specify the FQDN of your on-premises Exchange server and RPC proxy server. You have to successfully connect to the source server to continue.

    Exchange Online creates a new migration endpoint using the connection settings that were successfully discovered or that you provided manually. By default, this migration endpoint is configured to support 20 maximum concurrent migrations.

  7. On the Move configuration page, type the name of the migration batch, and then click Next. This name will be displayed in the list of migration batches on the Migration page after you create the migration batch. Batch names can’t contain spaces or special characters.
  8. On the Start the batch page, do the following:
    1.  Click Browse to send a copy of the migration reports to other users. By default, migration reports are sent to the administrator who creates the migration batch. You can also access the migration reports from the properties page of the migration batch.
    2.  Specify one of the following options to start the migration batch after it's created:
    3.  Automatically start the batch The migration batch is started as soon as you save the new migration batch. The batch is first marked with a status of Created; the batch is changed to a status of Syncing after it's been started.
    4.  Manually start the batch later The migration batch is created but it's not started. The status of the batch is set to Created. To start a migration batch, select it on the migration dashboard and then click Start Start Icon
  9. Click New to create the migration batch.

The new migration batch is displayed on the migration dashboard.

3. Start the Migration Batch

  1. In the EAC, navigate to Recipients > Migration.
  2. On the migration dashboard, select the batch, and then click Start Start Icon.

4. Convert On-Premise Mailbox to Mail enabled users

After a migration batch has finished running and you’ve verified that all mailboxes in the batch are successfully migrated and the initial synchronization of mailbox items to Exchange Online is complete, it’s recommended that you convert the on-premises mailboxes in the migration batch to mail-enabled users. Why? After a staged Exchange migration, a user has an on-premises mailbox and an Exchange Online mailbox. Because mail sent to the user’s on-premises mailbox is forwarded to their Exchange Online mailbox after migration, users need to connect to their Exchange Online mailboxes to access their email. But if a person uses Outlook to open their mailbox, the Autodiscover service still tries to connect to the on-premises mailbox. After you convert on-premises mailboxes to mail-enabled users, the Autodiscover service uses a mail-enabled user to connect Outlook to the Exchange Online mailbox after the user creates a new Outlook profile.

Another important reason to convert on-premises mailboxes to mail-enabled users is to retain proxy addresses from the Exchange Online mailboxes by copying proxy addresses to the mail-enabled users. This lets you manage cloud-based users from your on-premises organization by using Active Directory. Also, if you decide to decommission your on-premises Exchange organization after all mailboxes are migrated to Exchange Online, the proxy addresses you’ve copied to the mail-enabled users will remain in your on-premises Active Directory.

5. Delete 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 Exchange Online 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. The batch is removed from the list of migration batches on the migration dashboard.

  1. In the EAC, navigate to Recipients > Migration.
  2. On the migration dashboard, select the batch, and then click Delete Delete icon.

6. Complete Post Migration Tasks

  1. Assign licenses to Office 365 users. 
  2. Create an Autodiscover DNS record. 
    1. Alias autodiscover
    2. Target autodiscover.outlook.com
    3. Configure your MX record to point to your Office 365 organization. 
  3. Decommission on-premises Exchange servers.