How to Migrate from Exchange Server 2010 to Microsoft 365 (Complete Guide)

The Exchange Server 2010 – as you’re aware – has reached its end of support on October 13, 2020. This means this server version is no longer getting any security updates or patches. It has, thus, become urgent to move to Microsoft 365. For this, the recommended methods are staged migration and cutover migration. Though you can also use hybrid migration, it requires the Exchange 2010 SP3 Rollup Update RU11 or later.

Important: Only email data is migrated automatically in a standard cutover or staged batch. Calendar items, contacts, tasks, and public folders require separate steps.

For a full comparison of all Exchange migration methods, see our Exchange to Microsoft 365 migration guide or the Microsoft migration methods overview.

Why Migrate from Exchange 2010? (End of Life Urgency)

The Exchange Server 2010 end of life and end of support was on the 13th of October 2020. Since there are no more releases of security patches, bug fixes, and feature updates since this date, this makes it obsolete and vulnerable. Modern versions of Outlook, mobile devices, and operating system require technologies are no longer supported. This also adds to the security of the system where vulnerabilities are not mitigated and there is no support from Microsoft of the system. The server faces big security risks, if it keeps running.

Modern authentication is not supported on an Exchange Server 2010, meaning that it uses legacy Basic Authentication. This has been deprecated by Microsoft across M365. Looking at this alone, this creates a security gap that cannot be patched. The users, data, and company’s reputation are at risk of easy access, if the password is leaked or the computers get compromised.

Outlook Anywhere (RPC over HTTP) service has been deprecated. This means that newer versions of Microsoft Outlook may eventually drop support and you will need to use outdated user application which will result in a server and client security gap.

Looking at the above, apart from the security risk on the technical matter, you must consider that running unsupported systems in a heavily regulated industries (healthcare, finance, etc.) may violate compliance requirements. This will lead to hefty fines from the regulatory bodies and brand damage to the company, apart from the loss of business. When it comes to cost, if you have an on-site data center, this would involve maintenance and keeping the lights on for aging hardware and software. Supplier and vendor support is very limited while there will be no support from Microsoft, in case something happens. Migrating to Office 365 with a subscription-based model will convert the cost to Operational Expenditure (OpEx), where you will only be billed for what you consume while the maintenance, resilience, hardware upgrade, and other infrastructure costs and operations are handled by Microsoft with their SLA and no downtime.

Note: When migrating from an Exchange Server 2010 to Office 365, you should consider the upgrade of the Microsoft Outlook in the equation before the migration takes place. This is because, as of now, only Microsoft Outlook 2021 onward is supported on Microsoft 365 if these are fully updated.

What Migrate and What Doesn’t (Exchange 2010-Specific)

The Exchange Server 2010 – already reached end of life and support – has limited migration options and support, when it comes to hybrid setup. Before starting any migration process, you need to review the tabled below. The items marked as ‘No’ are not supported and you need to use a third-party tool.

Tip: The specialized tool – Stellar Migrator for Exchange – can help in migrating complete mailbox data, including Calendar, Contacts, and Tasks, and even public folders directly. This reduces the complexity and manual steps for the above items which are marked as No.

Things to Know before Migration (Exchange 2010-Specific)

Exchange Server 2010 has become obsolete. Therefore, there could be underlying things that can impact the migration process. So, before you start the migration, see the table for the prerequisites needed.

Methods to Migrate Mailboxes from Exchange 2010 to Microsoft 365

Here are the methods – you can follow – to perform Exchange 2010 to M365 migration.

Method 1: Staged Migration (Recommended)

This is suitable for Exchange 2003, 2007 and 2010, and when you have to migrate over 2000 mailboxes. In this, you will need to synchronize the data from the onsite server to Microsoft 365 in stages. When the synchronization of all the batches is complete, you need to cut over the MX records to the Office 365 and re-configure the user’s accounts in one go. To perform this method, follow these instructions:

Step 1 – Prepare your Exchange Server 2010

• Meet the prerequisites mentioned above.

Step 2 – Setup of Microsoft Entra Connect

• Installation of the Microsoft Entra Connect.
• Setup of Password Hash Sync.
• Ensure UPN Suffix are setup.
• Primary and secondary emails match.

Step 3 – Create Migration Endpoint

• Creation of the Outlook Anywhere migration endpoint.
• Testing the credentials of the migration user.
• Save the endpoint.

Step 4 – Create the Migration Batches

• Prepare the CSV files with the batches.
• Create the batches and assign the endpoints.
• Start the batches and monitor the progress.
• Repeat for each migration batch.

Step 5 – Complete Migration and Switch Mail Flow

• Change the MX records and Autodiscover records.
• Update the SPF record to include the Microsoft 365.
• Configure Outlook on each client.

Note: Theprofiles in Outlook for migrated users in Exchange 2010 do not auto-update. You (the administrator) have create a new profile for every user or run the Outlook auto-configuration, once the batch is completed.

To know more, read Staged Migration: Migrate Exchange Mailboxes to Office 365.

Method 2: Cutover Migration

This method is suitable for migrating fewer than 2000 mailboxes. It involves changing the MX records and migrating the data. Nevertheless, it is suggested to move less than 150 mailboxes for optimum result. Here’s how to perform this process.

Step 1 – Prepare your Exchange Server 2010

• Meet the required prerequisites.

Step 2 – Create Endpoint and Start the Migration Batches

• Create the endpoints for the local to cloud.
• Create and run the migration batches.
• Monitor the migration batches.
• Complete the migration batches.

Step 3 – Change the MX Record to Point to Microsoft 365

• This needs to be done prior to the migration of data with the MX record and the Autodisover.
• This needs to be planned outside office hours.

Step 4 – Setup of the User’s Outlook Profiles

• This needs to be done by the migration team where the Microsoft Outlook profile needs to be configured for each user.

Step 5 – Migrate the Local Data

• After the migration of the DNS records, the users will be receiving and sending emails from Microsoft 365.
• Create the migration endpoint and start the migration of data.

Read Cutover Migration: Migrate Exchange Mailboxes to Office 365 to know more about this method.

Caution: This process may cause a brief interruption of service, during the MX records propagation. So, you should always plan the migration during off-business hours.

Legacy Public Folder Migration (Exchange 2010-Specific)

In this section, we are going through the process of migration of public folders. This migration cannot be done the same way as the standard mailbox migration method. You need to use specific scripts for Exchange 2010 public folder migration. Let’s see the stepwise process to migrate public folders.

Step 1 – Acquire the Scripts

• Download the scripts from the Microsoft site.

Step 2 – Take Inventory of all the Public Folders

• Prepare the public folders and get the sizes.
• Sanitize the current folders.
• Cleanup process.
• Use the scripts to validate the folders.

Step 3 – Export the Folder Statistics and Hierarchy

• Run the script to get the statistics.
• Run the script to get the hierarchy.
• Confirm the results.

Step 4 – Generate the Public Folder Mapping

• Use the script to generate the mapping.
• Input the exports from Step 3.
• Specify the target.
• Generate the mapping file.

Step 5 – Create and Run the Migration Batch

• Use the script to create the public folders on cloud.
• Start the migration batch script.
• Monitor the progress.

Step 6 – Lock Public Folders (Local) and Complete Migration

• Lock the local public folders to read only.
• Complete the migration process.
• Enable the Exchange Online public folder.

For the full legacy public folder migration guide, see How to Migrate Public Folder to Office 365 . For the official Microsoft migration scripts, see Use batch migration to migrate legacy public folders (Microsoft Learn).

Methods Comparison Table

The below table compares the four migration methods which are available for Exchange Server 2010.

Post-Migration Checklist

Once you’ve migrated the data, perform the following tasks to finish the migration process.

Note: These are needed due to the legacy client support requirement of Exchange Server 2010.

Use Stellar Migrator for Exchange

With the Exchange Server 2010 being a few years out of support and end of life, the migration process gets a little bit more complicated since there is no support from Microsoft and other vendors. There are some limitations and pain points related to Exchange Server 2010 migration which you should be familiar with and which you might encounter during the migration. Here is where Stellar Migrator for Exchange can assist and improve the migration process with less complication and without major changes.

• Exchange 2010 EOL means no Microsoft support if migration fails midway. Stellar Migrator for Exchange has the auto-reconnect feature on failure which is critical here. If the process is interrupted, it will continue from where it stopped. Apart from this, Stellar Migrator for Exchange supports all versions of Exchange Server.
• Calendar, contacts, and tasks don’t migrate with native methods. Stellar Migrator for Exchange migrates the full mailbox in one job including user mailboxes, user archives, and shared mailboxes.
• Legacy public folder migration is complex and script-based. With Stellar Migrator for Exchange, it requires just a few clicks without any scripting.
• Outlook 2007/2010 profile reconfiguration is manual after native migration. This can be resolved using the Stellar Migrator for Exchange features like incremental migration to reduce the reconfiguration window.
• Exchange 2010 Server has throttling limits which slow down large migrations whereas Stellar Migrator for Exchange processes up to 10 mailboxes concurrently including Incremental (Delta) data migration process.

Conclusion

In this detailed guide, we have explained the recommended methods – cutover and staged – for migrating from Exchange Server 2010 to Microsoft 365. As this server version is out of support, you may face various issues when migrating using the native methods. For hassle-free migration, you can use Stellar Migrator for Exchange – a specialized tool that can migrate data from any Exchange version to Office 365.