Exchange 2010 Decommissioning After Migration to Exchange 2013

I'm finally getting around to decommissioning one of our Exchange 2010 environments after migrating to Exchange 2013. I thought I'd share the steps involved to ensure you have completely removed the legacy servers and don't have any orphaned objects hanging around.

The order we'll go in is:

1. Edge Transport Servers
2. Client Access/Hub Transport Servers
3. Mailbox Servers
4. Management Tools on Workstations

Removing the Edge Server:

Make sure that no mailflow is going through the server(s) by using message tracking logs.

Remove the Edge Subscription by running the following command in the Exchange Management Shell (EMS):

Remove-EdgeSubscription -Identity EdgeServer01

**Note** Change "EdgeServer01" to the name of your Edge Server

Go to Programs and Features and run the Uninstall. It will check readiness and then proceed to remove the Edge Role.

Removing Client Access Servers (CAS)/Hub Transport Servers:

In my environment (and most that I've worked on) CAS and HT are installed on the same machine, so we'll be removing them together.

CAS can be removed after they are not serving any clients. You can check the IIS logs to make sure that there are no new connections.

**Note** You will see connections from your Exchange 2013 environment, but that's ok to ignore.

Hub Transport (like the Edge) can be removed after there is no more mailflow. Check message tracking logs to make sure.

**Note** You will see some traffic if there are relay connectors still on the server, or there are DNS entries still pointing to SMTP.

Go to Programs and Features and run the Uninstall. It will check readiness and then proceed to remove the CAS and HT Roles.

Removing Mailbox Servers in a DAG:

Mailbox servers can be removed when there are no mailboxes, no Public Folders, and the Offline Address Books have been removed.

Remove any legacy Offline Address Books by going to Organization Config > Mailbox > Offline Address Book. Right-click the OAB and select "Remove".

Remove the Public Folder Database by running the following in the EMS:

Get-PublicFolderDatabase -Server Mailbox01| Remove-PublicFolderDatabase

**Note** Change "Mailbox01" to your mailbox server name.

Breaking the DAG involves these steps:

1. Removing database copies from the server (unless it is the last DAG member hosting the single copy of the databases)
2. Removing the databases
3. Removing the member from the DAG
4 .Removing the DAG object Active Directory
5. Uninstalling the Mailbox Role

Remove Database Copies:

To remove database copies, move all active copies to another mailbox server:

Move-ActiveMailboxDatabase -Server Mailbox02

Remove the copies from the server:

Get-MailboxDatabaseCopyStatus -Server Mailbox02 | Remove-MailboxDatabaseCopy

Disable Datacenter Activation Coordination (DAC) mode:

Set-DatabaseAvailabilityGroup -Identity DAG01 -DatacenterActivationMode Off

Remove Mailbox Databases:

Remove Mailbox Databases after verifying that they no longer host any mailboxes, by running:

Get-MailboxDatabase -Server Mailbox01

Remove-MailboxDatabase DB01

Remove-MailboxDatabase DB02

Remove-MailboxDatabase DB03

**Note** Change "Mailbox01" to your server name, and "DB01-03" to your database names.

Remove the server from the DAG:

Remove-DatabaseAvailabilityGroupServer -Identity DAG01 -MailboxServer Mailbox02

**Note** Change "DAG01" and "Mailbox02" to match your environment

Repeat the above steps for each DAG member.

Remove the DAG object:

Remove-DatabaseAvailabilityGroup DAG01

After removing the servers from the DAG and removing the databases, you can uninstall the Mailbox Role. Go to Programs and Features and run the Uninstall. It will check readiness and then proceed to remove the Mailbox Role.

Uninstall Exchange Management Tools on Workstations:

Go to Programs and Features and run the Uninstall. It will check readiness and then proceed to remove the Exchange Tools Install.

Now your Exchange 2010 to 2013 is complete!