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Exchange Server Error: An Incomplete Installation Was Detected

I ran into an interesting issue while I was removing an Exchange 2016 server from an environment. The uninstall process failed on step 5 of 13 and threw an error. The error itself is not all that important for this article, since there are many different errors that might put you in the same position I found myself in, rare as that may be.

When Exchange setup fails on an uninstall the first thing you would logically try is another uninstall. Unfortunately, Exchange setup now throws an error message that…

An incomplete installation was detected. Run setup to complete Exchange installation.

Taking Exchange at its word, I tried to reinstall the partially uninstalled server by running setup again.

Thinking back to other Exchange setup-related disasters I’ve encountered, I remembered that Exchange stores some information about setup progress in the registry. There’s a tip about it here on the Exchange Masters blog. Setup is failing on the Front End Transport service in my case (see above), which is the “FrontEndTransportRole” in the registry.

After removing the Action and Watermark entries, I tried the Exchange install again. This time setup was able to complete the installation, which repaired the server. I was then able to run setup again to uninstall the server, which was successful.

Now, during all this I was asked whether we could just power off the server and remove it using ADSIEdit. As you hopefully already know, removing an Exchange server (or really, doing anything at all) in ADSIEdit is an unsupported method. Sure, there’s lots of war stories out there where people have gotten away with it and everything has continued to work okay in their environment (as far as they can tell), but I would never recommend it and certainly don’t do it for customers.

If you did have a server that was beyond repair and wanted to cleanly remove it from your environment in a supported manner, the correct approach is to use a recovery install. Recovery installs are available for all of the current versions of Exchange, and there’s really no excuse for not doing one if the scenario calls for it.

Paul is a Microsoft MVP for Office Servers and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul is a co-author of Office 365 for IT Pros and several other books, and is also a Pluralsight author.
Category: Exchange Server


  1. Asif Saleem says:

    Hello Paul,

    I had a situation where prior to uninstalling the old exchange 2013 it died. though the new server is running fine. I would like to know how can we removed the traces of the dead exchange 2013 from our organization. I saw many articles for utilizing the adsiedit but nothing from Microsoft. can you please help me out

  2. Elizabeth says:

    Hi Paul, Thanks for your great articles. I have the same situation right now with an Exchange 2013. Mine Failed because it couldn’t stop the Transport Service. So that registry entry is there (Action REG_SZ Uninstall). Just to be clear, do I delecte the whole entry? Also in your example above, you tried Setup.exe /mode:install, but it shouldn’t it be mode:recovery? Also, do I need to reset the AD account for the server? or can I just simply do this on this same server:
    1) Delete the Registry Key
    2) Run setup.exe /mode:Recovery /IacceptExchangeServerLicenseTerms

    I appreciate the help. First time recovering an Exchange server.

    • Elizabeth says:

      Hi Paul, I had bit more time to think and I apologize. 🙂 Yes, you do a /M:Install because its that same server, and so no AD reset either. I will do this only if I was installing Exchange in ANOTHER server. One more thing: I have a co-existence with Ex2016, so it will allow me to re-install 2013 anyways without breaking anything right? Thanks in advance.

        • Elizabeth says:

          hi Paul, since is an Exchange 2013, I tried reinstalling typing setup.exe /m:install /r:clientaccess,Mailbox /IacceptExchangeServerLicenseTerms but it complained that the Client Access Role was already present. So I omitted the Client access and just typed /r:mailbox. When it gets to certain percentage it fails with an error exactly like this:

          [07/19/2015 00:58:47.0354] [1] [ERROR] The following error was generated when “$error.Clear();
          $defaultPort = 25;
          $localServer = get-exchangeserver $RoleFqdnOrName -DomainController $RoleDomainController;

          if ($localServer.IsFrontendTransportServer)
          Write-ExchangeSetupLog -Info “Using port 2525 for the default hub receive connector since frontend role already present.”;
          $defaultPort = 2525;

          $bindingString1 = ‘’ + $defaultPort;
          $bindingString2 = ‘:::’ + $defaultPort;
          $binding1 = new-object Microsoft.Exchange.Data.IPBinding $bindingString1;
          $binding2 = new-object Microsoft.Exchange.Data.IPBinding $bindingString2;

          -Name ("Default " + [String][System.Environment]::MachineName )

          -MaxRecipientsPerMessage 5000
          -Fqdn $RoleFqdnOrName

          -Bindings $binding1,$binding2

          -DomainController $RoleDomainController
          -MaxInboundConnectionPerSource Unlimited

          -MaxInboundConnectionPercentagePerSource 100 `
          -SizeEnabled EnabledWithoutValue;
          ” was run: “Active Directory operation failed on Server.walhouse.local. The object ‘CN=Default SERVER,CN=SMTP Receive Connectors,CN=Protocols,CN=SERVER,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=Walhouse,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=walhouse,DC=local’ already exists.”.
          [07/19/2015 00:58:47.0354] [1] [ERROR] Active Directory operation failed on Server.walhouse.local. The object ‘CN=Default SERVER,CN=SMTP Receive Connectors,CN=Protocols,CN=SERVER,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=Walhouse,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=walhouse,DC=local’ already exists.
          [07/19/2015 00:58:47.0354] [1] [ERROR] The object exists.
          [07/19/2015 00:58:47.0354] [1] [ERROR-REFERENCE] Id=BridgeheadComponent___a525250ab5a4442c868ad368c34aad21 Component=EXCHANGE14:\Current\Release\Shared\Datacenter\Setup
          [07/19/2015 00:58:47.0354] [1] Setup is stopping now because of one or more critical errors.

          I really appreciate the help. This is an standalone server ready to be decommissioned.

          • Hard to say since I don’t know what happened in the lead up to this issue.

            If it’s a server you’re trying to decom you could consider just wiping the server, reinstalling a fresh OS, doing a recovery install, then a clean uninstall.

            Or consider opening a support case with Microsoft to see if they’ve got a better suggestion.

  3. Elizabeth says:

    Will do that. Thanks so much for your Guidance Paul. And just so you know all this mess happened because when uninstalling Exchange, setup couldn’t stop the MSExchange Transport Service. It was stuck at Stopping. And eventually failed Setup failed. I think what I learned is that in the future I will make sure I reboot the servers before I uninstall Exchange, to have everything fresh. 🙂 Have a good day Paul.

    • Elizabeth says:

      Hi Paul and just to post how I solved it: I login into EAC and under Mail Flow>Received connectors> I deleted the 2 receive connectors for the Hub Transport role (Mailbox) for that server that the installation was complaining about that already existed. After that I was able to ran setup again and it worked! So it looks like the original failed uninstall process partially got rid off the mailbox role but left behind those 2 items (Connectors). Many thanks for your help, I learned a lot. I really appreciated.

  4. Aleksey says:

    Hi, Paul.
    So far my Exchange 2016 experience was smooth, I don’t know if what I write here can be applied to 2016. But with Exchange 2013 it happened often enough.

    Microsoft is very missleading (as usual).
    “An incomplete installation was detected. Run setup to complete Exchange installation.”

    What this actually means is that you shouldn’t open control panel, click uninstall programm, etc… You need to extract the distribution of your current version of exchange and run setup.exe in uninstalation mode.
    Like “.\setup /m:uninstall”.

    So far so good. Always worked for me, when normal uninstallation fails for any reason.

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