Live Chat by BlueShield
Template for Staged Migration in Office 365
Posted by Mandeep Singh, Last modified by Mandeep Singh on 12 August 2017 11:06 PM

Things to Remember: -

  1. Dirsync should be enabled.
  2. Staged Migration will only migrate Primary and resource mailbox unlike cut-over migration.
  3. Here Distribution Groups, Mail Contacts and Mail-enabled users are migrated using Directory Sync tool.
  4. Here we have to create CSV file unlike cut-over migration.
  5. We can use staged migration only to migrate mailboxes from Exchange server 2003 and 2007.
  6. We can use this tool if we have Exchange server 2010 and 2013, since in Exch Server 2010 and 2013 we cannot change TargetAddress Attribute.
  7. RPC/HTTP or Outlook Anywhere should be enabled.
  8. UM should be disabled on mailboxes which we are going to migrate.


What happens when we start the Staged Migration: -

  1. While creating a Migration batch, we create a CSV file. It contains the list of mailboxes that we need to migrate to Exchange online.
  2. Once the Migration Batch is started it does following.
  3. Initial Synchronization: -
    1. It will check if Dirsync is enabled.
    2. Verifies if Mail-Enabled users are present in Office 365 for corresponding users in CSV file. Mail-Enabled users are automatically created by Dirsync. We don’t need to create it manually.
    3. Converts those mail-enabled users into Exchange Online Mailbox users.
    4. Configure TargetAddress attribute on corresponding Local on-premises mailboxes mentioned in CSV file. This will enabled Mail Forwarding from local Exchange mailbox to Cloud Mailbox.
    5. During Initial Sync all the local Emails, Contacts and calendars for mailboxes are migrated to cloud.
  4. Once the initial sync is completed, an email sent to administrator with the status of batch. It will contain the list of mailboxes which are migrated successfully and mailboxes which failed to migrate.
  5. Now all new emails will get forward to Exchange online mailboxes because of Target Address Attributed. TargetAddress attribute contains email address of Exchange Online mailbox.
  6. But even after migration batch is complete, we cannot change the MX record and CNAME record to Office 365, since we still have people using mailboxes on local Exchange server.
  7. Hence we have to convert the local mailbox user into Mail-Enabled user. Hence the entire auto-discover request will get forwarded from local Exchange mail-enabled user to Exchange Online mailbox.
  8. Now we will be able to configure outlook profile using auto-discover for migrated users.
  9. Similarly we can create multiple Staged migration batches for remaining users.
  10. After all the users are migrated to cloud, we can change the MX and CNAME record.     

POST migration Task:-

  1. Assign License to Users in Office 365.
  2. Create CNAME record for auto-discover and MX record for Mail Flow. 
  3. Decommission on Premises Exchange server. This step is optional.

(0 vote(s))
Not helpful

Help Desk - BlueShield Technologies