Microsoft Exchange Server 2010 reached its end of life and support on October 13, 2020, which means it no longer gets any new features, security fixes, bug fixes, and so on. This is prompting the organizations to migrate to Office 365 (Microsoft 365) as it offers enhanced scalability and security. However, migrating from Exchange 2010 to Office 365 requires careful planning, extensive monitoring, and choosing the right method depending on the organizational structure. In this article, we will explore various migration approaches that can help you in migrating mailboxes from MS Exchange 2010 to Office 365.
Methods to Migrate Mailboxes from Exchange 2010 to Office 365
Microsoft offers Microsoft 365 and Office 365 mail migration advisor that can help migrate mailboxes from on-premises Exchange Server to Microsoft 365. This tool is suitable only if you have a single-forest, single-domain environment, and not a complex Active Directory system with child domains or other configurations. You can use this tool to migrate from your Exchange 2010 to Microsoft 365. In addition, we have mentioned below some other migration methods that you can use based on your setup and downtime needs.
Method 1: Cutover Migration
The Cutover Migration method is a straightforward approach for migrating mailboxes from Microsoft Exchange Server 2003 and later versions to Office 365 or Microsoft 365. This method is ideal for organizations looking to move their entire email infrastructure at once, rather than in phases. It supports migration of up to 2,000 mailboxes, though Microsoft recommends migrating 150 or fewer mailboxes to ensure smooth transition and minimize potential delays.
This migration method is quite simple where you just need to set up synchronization between your Exchange Server and Office 365. However, before you start the migration process, there are a number of configurations to be done. One of which is a clean and perfectly running Outlook Anywhere. Also, make sure that directory synchronization and unified messaging are disabled. Here are the steps to perform cutover migration:
Step 1: Enable Outlook Anywhere
Exchange 2010 to Office 365 migration is dependent on properly running Outlook Anywhere. In the later Exchange Server versions, it is enabled by default. But in Exchange 2010, if you have not configured it, you need to do it. Here’s how:
- To set up Outlook Anywhere, you need to install an SSL certificate (not self-signed) and the RPC over HTTP component on the server hosting Exchange.
- To set up this, expand the Server Configuration/Client Access and right-click on your server in the Client Access area in the middle section.
You can test it at a later stage from your Office 365 portal.
Step 2: Assign Proper Permissions
The next step is assigning the required permissions to the user that you will be using to migrate.
- For this migration, you need to find the ApplicationImpersonation, View-Only Configuration (on both Exchange Server and Office 365), View-Only Recipients, and User Management Administrator on Office 365.
- The impersonation can be performed via the Exchange Management Shell by using the below command.
New-ManagementRoleAssignment –Name:impersonationAssignmentName –Role:ApplicationImpersonation –User:<Your migration user>
- You need to also create a mail-enabled security group in Office 365. This is required during the migration process as the service will not be able to provision any migrated groups as security groups in Office 365 as these do not exist.
Step 3: Verify your domain in Office 365
Now, you need to verify your domain in Office 365. This will not make anything live, just a confirmation of ownership by adding either an MX or TXT record. Now, Microsoft has introduced a feature to verify domain through email verification, where an email is sent to the owner of the domain.
Step 4: Create a Migration Endpoint
Once you have verified the domain, create a migration endpoint that contains all the information to connect your Exchange 2010 to Office 365.
Step 5: Start the Migration
After you create the endpoint, you need to create and start a migration batch. This batch will include all the mailboxes that need to be migrated. This is the point where the migration happens and the data is transferred. To make sure that everything is migrated, you need to assign an Office 365 license to a user, log into the user, and verify that the data is in the mailbox. After you have transferred all the data, it is time to make the switchover.
Step 6: Clean up the DNS
You need to clean up the DNS after the migration. This can be done by pointing the MX record to Office 365, along with CNames, TXT records, and SRV records. For this, you need to modify your current setup to stop pointing your DNS Autodiscover and SCP to your Exchange 2010 setup.
You can now safely remove the batch and decommission your servers.
Method 2: Hybrid Migration
Hybrid Migration is a migration approach that enables organizations to move on-premises Exchange mailboxes to Office 365 while maintaining the mailbox access. This method allows businesses to integrate their existing Exchange environment with Microsoft 365, ensuring smooth coexistence between on-premises and cloud-based mailboxes. Hybrid migration provides a shared address book, and free/busy calendar sharing, making it an ideal choice for organizations that require a gradual transition to the cloud while retaining some on-premises infrastructure.
The hybrid migration method enables on-premises Exchange and Office 365 to co-exist at the same time. However, this is only available for Exchange Server 2010 onwards and is recommended when you have large amount of data to migrate to Office 365.
This method is not an intermediate stage as you cannot keep both sides or use it as a failover. The hybrid method is a final deployment. For this, you need to configure a dedicated Hybrid Configuration Wizard (HCW), which includes a federation trust between Exchange and Office 365, organization relationship, MRS proxy, and connectors. However, if you have large amount of data to transfer, apart from the time to transfer, it requires administrative efforts to set it up and to transfer the data.
Method 3: Use a Specialized Exchange Migration Tool
For a smooth and quick migration, you can use Stellar Migrator for Exchange – a specialized Exchange migration tool designed to simplify mailbox migration from Exchange Server to Microsoft 365, with zero downtime and no data loss. The tool supports multiple migration scenarios, including cutover, staged, hybrid, cross-forest, and cross-domain migrations, ensuring flexibility for organizations of all sizes. The tool directly migrates user mailboxes, archives, and public folders, from Exchange to Office 365 with automated mailbox mapping.
Unlike complex manual methods that require extensive PowerShell scripting and planning, Stellar Migrator for Exchange provides a user-friendly interface, automated migration experience, real-time tracking and reporting, while ensuring a secure and smooth transition to Microsoft 365.
This tool can also be used for local Exchange to Exchange migration, Microsoft 365 to Microsoft 365 migration, and Microsoft 365 to local Exchange migration.
To know how the tool works, read: How to Use Stellar Migrator for Exchange
Comparison between Manual Migration Methods and Stellar Migrator for Exchange
Below is a comparison between the manual migration methods and Stellar Migrator for Exchange based on different features:
| Feature | Cutover Migration | Hybrid Migration | Stellar Migrator for Exchange |
| Size of Organization | Suitable for small organization with tight timeline | Large enterprises with coexistence needs | All sizes of organizations needing a reliable, low-complexity migration |
| Migration Type | Manual (all at once) | Manual, complex setup with coexistence | Direct, GUI-based |
| Technical Complexity | Moderate (PowerShell + DNS) | High (SSL, DNS, AD Sync, and HCW) | Very low (Intuitive GUI) |
| Downtime | Moderate to High | Low but heavy configuration | No downtime |
| Preview Mailbox Content before Migration | Not supported | Not supported | Supported |
| Public Folder and Archive Migration | Not supported | Partially supported, needs manual work | Supported |
| Auto-Reconnect on Failure | Not supported | Requires manual intervention | Supported |
| Parallel Processing (Concurrent Mailboxes) | Not-Supported (sequential) | Limited support (depends on batch scripting) | Supported (up to 10 mailboxes at once) |
| Migration Speed | Slow | Moderate (setup takes time, migration is gradual) | Fast (parallel and incremental) |
| Resources Required | Basic admin setup and downtime coordination | High (SSL, Azure AD Connect, public IPs, etc.) | Minimal (a single person can perform the migration) |
| Support for Exchange Versions | 2003–2010 only | 2010 and newer | 2010, 2013, 2016, and 2019 |
| Incremental Migration | Not supported | Supported | Supported |
| Cross-Forest and Cross Domain Migration | Not supported | Not supported | Fully supported |
| Number of Mailboxes Limit | Limited to 2000 mailboxes officially | No fixed limitation | No limitation (Number of mailboxes that can be migrated depends on the number of licenses) |
Conclusion
When it comes to Exchange Server 2010 to Microsoft 365 migration, you can use cutover or hybrid migration method as explained above. However, these methods are complex and time consuming, and requires technical expertise for successful completion. To avoid these drawbacks, you can use an Exchange migration tool, like Stellar Migrator for Exchange that simplifies mailbox migration from Exchange Server to Office 365 and vice-versa with zero downtime and no data loss. The tool ensures seamless migration of primary mailboxes, archives, and public folders, while preserving data integrity.
Was this article helpful?
