This article outlines the complete task flow for migrating mailboxes from On-Premises Exchange 2003 servers to Office 365. This task flow will not work for Exchange 2007+ or Hosted Exchange.
We strongly recommend that you use HealthCheck for Office 365 to check ahead of time to see if end user hardware and software is compatible with Office 365. HealthCheck for Office 365 is a free utility.
If this is your first time performing a migration, we have created a Migration Planning & Strategy Guide to walk you through planning, set-up, and general migration best practices.
If you have already completed the migration preparation, simply follow the steps below.
Preparing the Source
Preparing the Destination
Create A Project
The following options are most valuable for Exchange to Office 365 migration scenario:
- Set to use impersonation at Destination by checking the Use impersonation at Destination box.
- Set Maximum concurrent migrations: When Exchange 2003 is the Source server, it is very important that this number should be set to a low value, to ensure that the Source server does not run out of resources. To be very safe, we recommend initially setting this to 5. This means that when all mailboxes are selected and the migration begins, only the first five (5) mailboxes in the list will be migrated (using parallel processing), and then when the first of the five (5) completes, the next in the list will begin migrating, and so on down the list, through to completion of all mailboxes. If the Source server has enough server resources, set this parameter based on the bandwidth guideline of three (3) mailboxes per 1Mbps of bandwidth. Therefore, for example, if there is a 10Mbps connection, we recommend that the maximum concurrent migrations parameter be set to 30.
Run Retry Errors. Look through the user list and click any red "failed migration" errors.
Review the information and act accordingly. If problems persist, contact Support.
If not using DeploymentPro, users must create new Outlook profiles, and set up their signatures again, and reattach any PST files that were attached to their previous profile. Click the pie chart icon in the MigrationWiz dashboard to receive an email containing all the project migration statistics.