Microsoft Office Tutorials and References
In Depth Information
A cutover migration is initiated through the Exchange admin center (EAC) for the latest
release of Office 365. For organizations that are currently on Office 365 but have not been
upgraded to the latest release, this is done through the Exchange Control Panel (ECP). You
can also use Windows PowerShell to provision new Exchange Online mailboxes, and then
migrate mailbox data from your on-premises Exchange to Exchange Online.
Before we look at how a cutover migration is set up, it is useful for you to know what
happens when you execute a cutover migration. When a cutover migration is initiated, the
following processes occur:
● The migration service provisions new mailboxes in Exchange Online by reading the
on-premises Exchange 2003 or 2007 address book.
● On-premises distribution groups and contacts are migrated to Exchange Online.
● The migration service then migrates the contents, contacts, and calendar items from
on-premises mailboxes to their corresponding online mailboxes. This part of the
process is called initial synchronization.
● On-premises mailbox contents are synchronized with their corresponding
online mailboxes every 24 hours. This part of the process is called incremental
● When you are ready to complete the migration, change the MX record to start
routing emails to the online mailboxes and end the migration. Exchange will conduct a
final synchronization and notify the administrator through email that the migration is
complete. The email notification will contain two reports:
MigrationErrors.csv This report contains a list of mailboxes that failed to
migrate and information about the error.
MigrationStatistics.csv This report contains a list of mailboxes and the
corresponding number of items migrated. The report also includes a unique
password assigned to each mailbox that the user will need to change after
initial log on. Remember that this is because the cutover migration creates new
accounts as part of the migration process.
You have the option to use Autodiscover or manually configure connection settings prior to
initiating the cutover migration. Configuring Autodiscover was covered in Chapter 11.