What You Need to Know About a Staged Email Migration to Office 365 – Technical Guide

Microsoft users can migrate their email contents of mailboxes from their own mail system to Office 365 account. Well to perform the same, one will have to use staged migration. Staged migration is the process of moving on-premises mailboxes to cloud.

NOTE: To perform staged migration, the source email system should be MS Exchange server 2003, or MS Exchange Server 2007. Also you should have more than 2000 mailboxes to perform such migration.

Staged Migration Office 365 Prerequisites

Below-mentioned are some staged migration (Office 365) requirements:

  • With Azure Active Directory sync, accounts should be properly synchronized between domain of on-premises Active Directory and Office 365 for working with staged migration.
  • No other recipient types like distributed groups, contacts, and mail-enabled users cannot be migrated with staged migration procedure. Therefore, only the users mailboxes and resource mailboxes can be migrated.
  • The primary domain name should be verified to your Office 365 organization.
  • Out of Office messages are not moved with user mailboxes. If a user enables this feature before migration procedure, then the feature will be enabled in resultant mailbox, but the Out of Office message folder will be blanked.
  • To upgrade the performance of migration, connections should be limited to your email system. This limitation involves the client/server total connections, per-user connections, and IP address connection either on the firewall or the server. If you don’t want to limit the connections, then skip this procedure.

Different Migration Affect on Users

  • Administrators Can Gain Access On Email: Users will get access to mailboxes of source email system in order to perform migration.
  • Creation of New Microsoft Outlook Profile: After staged migration, all the mailboxes are moved and on-premises accounts are then converted to mail-enabled accounts. In MS Outlook, users should create a new Office 365 profile in order to connect Outlook & Office 365 accounts.

Staged Migration Office 365 Steps

To perform this email migration, we can use PowerShell to perform a staged migration to Office 365.

After Migration Setup Tasks

After performing successful staged migration to Office 365, below-mentioned are some activities that are to be performed:

  • Synchronize and create your on-premises users in Office 365, either with the help of Microsoft Azure Active Directory Synchronization Tool or MS Azure Active Directory Sync Services
  • In Exchange admin center, configure the Exchange server
  • After completion of migration, change your MX record of organization to Office 365. The MX records the mail system which is to determine location of system.

To end up with a staged email migration, you can use the following tricks:

  • Configure or verify that whether your directory synchronization is active or not
  • Examine whether your Outlook Anywhere is working or not
  • Creation of one or more lists of mailboxes for migrating to Excel
  • Systematically configure and start up the migration process


The blog is a complete technical guide which illustrates ‘What You Need To Know About A Staged Email Migration To Office 365?’. All the prerequisites are completely described in this blog and after fulfilling these requirements one can proceed to start staged email migration procedure.