Free Guide to Decommission Exchange 2010 After Migration

Once you have completed the migration of the Exchange Server, it’s important to decommissioning old MS Exchange Server properly from the organization to avoid any issues or problems which may arise due to orphaned objects.

Many of us consider uninstalling an MS Exchange Server, an easy process which can simply be accomplished through the Add/Remove Programs applet of the Control Panel. But it is not as simple as it seems because many issues may arise and thus, its mandatory to perform step by step decommissioning of the Exchange Server.

One of the reasons that uninstallation of Exchange Server is not a simple process because when we install the Exchange Server, it makes a lot of changes on the system, and when you have to uninstall or decommission Exchange 2010, all these changes need to be reversed manually.

Changes Made By Exchange Server During Its Installation

The following changes are caused by the installation process of the Exchange Server:

  1. The AD (Active Directory) Schema gets extended with the creation of the new class and attribute definitions.
  2. The registry file on the server gets modified and two of the registry keys are changed. These include HKLM\System\CurrentControlSet\Services and HKLM\Software.
  3. In AD, the configuration information also gets modified. In the “Services” section, under the “Configuration” partition, a new container is created with the name “Microsoft Exchange”. The Exchange Organizational Hierarchy is represented by this container.
  4. As soon as the Exchange Server is installed on a computer system, a folder hierarchy is created under the folder that was specified during the installation. This hierarchy contains the Exchange installation files
  5. In the Active Directory, some new user groups are created. For instance, in the MS Exchange Server 2000 and Exchange Server 2003, the two user groups which used to be created under the domain’s User Container include – Exchange Enterprise Servers and Exchange Domain Servers. In the MS Exchange Server 2007 and Exchange Server 2010, many new groups are created “Microsoft Exchange Security Groups”, a new organizational unit which is located in the forest’s root domain.

So, when you want to decommission the Exchange Server and uninstall it, some of these changes are required to be undone manually.

How To Manually Undo The Changes Which Occur On A Server Due To Exchange Server Installation?

Server Configuration Information In Active Directory

To remove the configuration information of the server from the AD, you can use the ADSI edit console, which can be accessed with the command ADSIEdit.msc.

When you are using the MS Server 2000 and Server 2003, it is one of the support tools and thus, it is not installed on the system by default. In Windows 2008, the ADSI Edit console is available by default.

How to remove the configuration information?

Install it if its not available by default and then open the ADSI Edit Console. Now, Navigate to “Services”, then click “Microsoft Exchange”, then the “Name of Exchange Organization”, then “Administrative Groups”. Next, click “Related Organizations Group”, then “Servers” where the ExchangeOrganizationName is being pointed as the name of your Exchange Organization.

Once the server that needs to be uninstalled is located, you can simply delete it to uninstall it.

Alternative Way To Delete Exchange Organization’s Information In the Active Directory

By deleting the Microsoft Exchange container, the information pertaining to the Exchange Organization in the Active Directory can be deleted. But, Microsoft does no support this way as one of the logical ways to remove a server. However, it can be done if you are instructed to do so by the CSS (Customer Service and Support) team of Microsoft.

This method also has the risk of leaving some partially mail-enabled or semi-deleted objects in the AD. While these objects can create a problem later on, but, if you don’t have any plans to install an Exchange Server into this forest again. But, if you are planning to do so, it can create some problems.

To mitigate the possible risks, you can try deleting the Microsoft Exchange Container either after deleting the mail-enabled objects or after moving them to another server.

Deleting the Root Folder Files

Delete all the files located under the root Exchange Server folder.

Deleting Registry Keys

Follow the below-given steps to delete the registry keys:

  • In Exchange Server 2000 and 2003, delete your HKLM\Software\Exchange key.
  • In Exchange Server 2007 and 2010, delete your HKLM\Software\Exchange Server keys and HKLM\Software\Exchange

Also, in the HKLM\System\CurrentControlSet\Services key, you need to delete the keys which were created to facilitate the Exchange Server services.

In Exchange Server 2000 and 2003, you are required to delete all the keys starting with MSExchange, and some keys also start with IMAP4Svc, POP3Svc, and RESvc.

In Exchange Server 2007 and 2010 all the keys pertaining to the Exchange Server Services start with MSExchange, like MSExchangeIS.

Deleting Exchange Server Related User Groups

While you can delete all the user groups pertaining to the Exchange server, but, it is not required. Your server or system, would not be affected even if these user groups aren’t deleted.

Undoing AD Schema Changes

While uninstalling or decommissioning the Exchange Server, you need not to worry about the AD Schema changes which were made during the process of the Exchange Server installation.

As the schema attributes and objects cannot be deleted, one cannot reverse these changes. Also, it’s not a good idea to reverse any of these changes. The reason is, that, if you have multiple Exchange Servers running, these schema attributes and objects will be required by them.

Even if you are not running any other Exchange Server, these schema attributes and objects need not to be deleted because they don’t create any problems. In fact, leaving the schema attributes and objects would be good because if you ever plan to install the Exchange Server again, it will take much lesser time as the changes in the schema would already be there.

Conclusively, uninstalling an Exchange Server after the migration is a lengthy process as you need to undo all those changes which were made to the server during the process of installation. Not all the changes that occur during installation are required to be undone, but, many of them should be reversed so that they don’t create any problems in the future when you want to use the server for any new installation.