I’m starting this blog post with a caveat: the process I’m going to describe here is not a good idea, goes against the advice of my colleagues (who have battle scars from when it’s been attempted in a live environment and not gone so well) and is certainly not recommended. In addition, I can’t be held responsible for any unintended consequences of following these steps.

Notwithstanding the above, I found myself trying to configure the Exchange Hybrid Configuration Wizard (HCW) in a customer environment, where the wizard failed because it was looking for servers that don’t exist any more.

I had two choices:

1. Recover the missing Exchange servers with setup.exe /m:RecoverServer, then uninstall Exchange gracefully (for 12 servers!).
2. Manually remove the servers using ADSI Edit.

I explained the situation to my customer, who discussed it with his Exchange expert, and they directed me to go for option 2 – this was a test environment, not production, and they were prepared to accept the risk.

Fearing the worst, I made a backup of Active Directory, just in case. This involved:

1. Installing the Windows Server Backup Command Line Tools feature on the domain controller.
2. Running wbadmin start systemstatebackup -backuptarget:driveletter:
3. Sitting back and waiting for the process to complete.

With a backup completed, I could then:

1. Run ADSI Edit.
2. Open the configuration naming context.
3. Navigate to CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=organizationname,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domainname,DC=tld
4. Delete the records for the servers that no longer exist.
5. Restart each of the remaining Exchange servers in the organisation in turn.
6. Check the server list in ECP.

(Incidentally, FYDIBOHF23SPDLT is “Caesar’s Cipher” for EXCHANGE12ROCKS).

Murat Yildirimoglu’s Windows IT Pro article entitled “How to Uninstall a Stubborn Exchange Server” goes into more detail, including completely removing an Exchange organisation from Active Directory, should that be required (Christopher Dargel covers that too).

The process seemed to work but the danger of manually removing servers from an Exchange organization like this is the potential side effects of “unknown unknowns” (which you can be sure won’t surface immediately). It did let me progress to the next stage of the HCW though. More on that in a future blog post…