How to Decommission Exchange Server 2010 After Office 365 Migration?

Microsoft 365 offers collaboration, ease, compatibility, and mobility without overthinking about the setup and the maintenance behind it. If you are still running an Exchange Server 2010, you need to migrate to a newer Exchange Server or Office 365 at the earliest, since Exchange Server 2010 is out of support and reached its end-of-life. This means that no new security patches or updates will be released by Microsoft. If there is a vulnerability, it can be exploited by hackers. Also, if a new feature is required for new devices or software, this will not be possible.

Migrating to Microsoft 365 is beneficial as you don’t have to maintain an operating system and physical server. You also need not to worry about the warranty and maintenance agreement, people to support the hardware, the Exchange Server and an Exchange Server admin, along with backups, support, licenses, and periodic upgrade including the disaster recovery plan and business continuity. Migration to Office 365 is not only beneficial to the business but also to the users as it offers several new features, functionality, and collaboration, especially with Teams. You need to also factor in the security behind the Office 365 tenant, including multi-factor authentication, auditing, and other security features included in the Enterprise Mobility Suite (EMS). This would not be feasible for a small or medium organization to implement on the on-premises setup.

If you want to migrate Exchange mailbox to Office 365 to Office 365, you need to do proper planning, considering all the factors and requirements, for smooth and successful process. Apart from the migration, you need to also think about proper decommissioning of the Exchange Server, without damaging the current Active Directory schema or leaving a lot of trails behind it. A clean uninstall is key to properly clean the Active Directory Schema.

Process to Decommission Exchange Server 2010 after Office 365 Migration

After the migration is complete and all the MX records have been updated, along with the user configuration, with the business fully working on Office 365, you need to remove all the mailboxes from the server. This can be done from the Exchange Management Tools or via the Exchange Management Shell (EMS) by running PowerShell commands.

After this is done, the mailbox database cannot be removed as there are arbitration mailboxes that need to be removed. To remove arbitration mailboxes, use the command below:

Get-Mailbox -Arbitration –Database | Disable-Mailbox –Arbitration –DisableLastArbitrationMailboxAllowed

Once this is complete, you need to remove the actual mailbox database from the server. This can be done by the following command.

Get-MailboxDatabase | Remove-MailboxDatabase

Correctly removing the Exchange Server from your system might take some time. This is needed since the Exchange Server is heavily dependent on the Active Directory Schema. Therefore, just shutting down the Exchange Server or decommissioning it will leave a lot of traces in your schema. After all the databases have been removed, you can do the clean-up from the Active Directory itself using ADSI Edit. It will allow you to manually remove the databases from the Exchange and Active Directory configuration. This may sound faster than removing them using the above, but it’s also more dangerous if something goes wrong, as there is no undo when using ADSI Edit.

The process involves the below steps:

• Right-click on Start.
• Click on Run and type ADSIEdit.msc.
• Open Configuration/Configuration Services.
• Open Microsoft Exchange/ <Your Organization>.
• Open Administrative Groups and Exchange Administrative Groups.
• Open Databases and delete the desired databases from the list.

This will remove all the mailbox and public folder databases from the system. Then, you need to remove any pending messages in your Exchange Server 2010 queue. These are messages which were not delivered for any reason or stuck in the queue. You need to use the following command:

Get-Message | Remove-Message

If all the above went well, the final step is to uninstall the Exchange Server from the Add Remove programs. There is only one thing you can do here is delete the virtual machine or turn off the server and unplug it.

To Conclude

If you’ve followed everything in this article, you should not have any issues and repercussion. If something happens during the uninstallation process, the error messages are self-explanatory and you should be able to get past them.

After the uninstall, if any mailboxes were not migrated or exported, it would be a big hassle to restore the whole server and export the mailboxes, since the Active Directory would need to be restored as well. Apart from that, if some data is missing after migration, it is a big administrative effort to restore them. With only the EDB file, you cannot do much since you cannot directly export from it. In this case, the right application to use is Stellar Converter for EDB which can open EDB files from any Exchange Server version without having Exchange Server installed. You can browse the EDB files and granularly export to PST and other formats. With Stellar Converter for EDB, you can export directly to any version of Exchange Server live database. You can also use it to migrate to Office 365.