You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Mailbox moves" entry in Mailbox Permissions.

You can use the New Remote Move Request wizard in the Exchange Management Console (EMC) on the hybrid server to move existing user mailboxes in the on-premises organization to the cloud-based organization:

1. Log on to: Cloud-based service administration portal
   
   
2. Assign a license to the user you want to move to the cloud-based organization. Learn more at: Activate synced users
   
   
3. In the console tree, click the Recipient Configuration node for the on-premises Exchange forest.
   
   
4. Click Mailbox, and select one or more user mailboxes from the Result pane.
   
   

   Note:

   By default, the Mailbox Replication Proxy service (MRSProxy) running on the hybrid server automatically throttles the mailbox move requests when you select multiple mailboxes to move to the cloud-based service. The total time to complete the mailbox move depends on the total number of mailboxes selected, the size of the mailboxes, and the properties of the MRSProxy. To learn more about customizing the MRSProxy, see: Throttling the Mailbox Replication Service

5. In the action pane, select New Remote Move Request.
   
   
6. On the Introduction page, view the mailboxes that you selected in the result pane. If you want to remove or add recipients, click Cancel, and then make the changes in the result pane.
   
   
7. Select Move only the user mailbox, and then select Next.
   
   
8. On the Connection Configurations page, specify the following settings:
   
   
   • Source Forest   This read-only field displays the on-premises organization on which the mailboxes that you are moving reside.
     
     
   • Target Forest   Select the cloud-based organization from the list.
     
     
   • FQDN of the Microsoft Exchange Mailbox Replication service proxy server in the source forest   Type the name of the externally accessible FQDN for the on-premises organization hybrid server on which the MRS proxy resides. For example, mail2.contoso.com.
     
     
   • Use the following source forest's credential   Enter the credentials of a recipient administrator who has permission to move mailboxes from the on-premises organization.   
     
     User Name   Type the administrator's domain and user name.   
     
     Password   Type the administrator's password.
     
     
9. Click Next to continue.
   
   
10. On the Move Settings page, for Target Delivery Domain, type the FQDN of the cloud-based service. For example, service.contoso.com.
    
    
11. Click Next to continue.
    
    
12. On the New Remote Move Request page, review the settings for this remote move request, and then click New.
    
    
13. On the Completion page, review the following, and then click Finish to close the wizard:
    
    
    • A status of Completed indicates that the wizard completed the task successfully.
      
      
    • A status of Failed indicates that the task wasn't completed. If the task fails, review the summary for an explanation, and then click Back to make any configuration changes.
      
      

    Important:
    You might receive a Microsoft Exchange Critical Error message telling you that Exchange couldn't load a type from an assembly. This is a known issue, and you can safely ignore this message. If a mailbox has a green check mark next to it on the wizard completion page, the move completed successfully.

After the mailbox move request reaches a status of Completed or Completed with warning, you must clear the move request to remove the InTransit flag from the mailbox. You won't be able to move the mailbox again until you clear the previous move request.

1. In the console tree, click the Recipient Configuration node for the cloud-based Exchange forest.
   
   
2. Click Move Request, and select one or more recipients that have a Move Request Status of Completed or Completed with warning.
   
   
3. In the action pane, click Clear Move Request.
   
   
4. A warning message appears confirming that you want to clear the move request. Click Yes.
   
   

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Remote mailboxes" entry in Mailbox Permissions.

You can use the New Remote Mailbox wizard in the EMC on the hybrid server to create user mailboxes in the cloud-based organization. If you want to create remote mailboxes, you'll have to use this wizard for each remote mailbox. You can't use the wizard to create multiple remote mailboxes.

Note:
You must have a remote domain configured as the target delivery domain for the cloud-based organization to complete the New Remote Mailbox wizard process.

1. In the console tree, click Recipient Configuration in the on-premises organization node.
   
   
2. In the action pane, click New Remote Mailbox.
   
   
3. On the Introduction page, select User Mailbox to create a mailbox that will be owned by a user to send and receive e-mail messages. Click Next to continue.
   
   
4. On the User Information page, specify the following settings:
   
   
   • First Name   Type the first name of the new user.
     
     
   • Last Name   Type the last name of the new user.
     
     
   • User logon name   Type the user logon name of the new user and select the primary SMTP domain used for your other on-premises users. For example, @contoso.com.
     
     
   • Password   Type the password.
     
     
   • Confirm password   Retype the password.
     
     
5. Click Next to continue.
   
   
6. On the Archive Mailbox page, make sure the Add an archive mailbox check box is not selected. Click Next to continue.
   
   
7. On the New Remote Mailbox page, review your configuration settings. Click New to create the remote mailbox.
   
   
8. On the Completion page, review the following, and then click Finish to close the wizard:
   
   
   • A status of Completed indicates that the wizard completed the task successfully.
     
     
   • A status of Failed indicates that the task wasn't completed. If the task fails, review the summary for an explanation, and then click Back to make any configuration changes.
     
     
9. Log on to: Cloud-based service administration portal
   
   
10. Assign a license to the new user. Learn more at: Activate synced users
    
    

When you move existing user mailboxes to the cloud-based organization, the successful completion of the New Remote Move Request wizard will be your first indication that moving the mailbox worked as expected.

Because the mailbox move process takes several minutes to complete, you can also verify that the move is working correctly by opening the EMC and selecting the on-premises organization Recipient Configuration node. Select the Move Request node to display the move status for the mailboxes selected in the New Remote Move Request wizard. The value of the Move Request Status is Moving during the mailbox move and is Completed when the mailbox has successfully moved to the cloud-based service organization.

Learn more at: View Move Request Properties

After the directory replication process has completed, you can check that the remote mailbox located on the cloud-based organization has been successfully created by verifying the mailbox properties. To do this, navigate to the Recipient node in the EMC for the on-premises organization and log on to the cloud-based service. Then, navigate to Admin Services > User Management > Users. The user mailbox should be available and configurable.

Having problems? Ask for help in the Office 365 forums. To access the forums, you'll need to sign in using an account that's granted administrator access to your cloud-based service. Visit the forums at: Office 365 Forums