Notes from the field: VMware Horizon instant clone breaks with Kerberos armoring

On my current customer project we’ve encountered a strange issue when some stricter security policies were implemented. Kerberos armoring was enabled which effectively broke the instant clone process for Windows 10 1809/1909 releases but not for 2009 or 21H2.

It all started with a ticket that the image update process in Horizon would error out and fail constantly on the mentioned images. On the newer builds no problem at all. At first we thought it was an Microsoft update of some sorts but after some troubleshooting with colleagues Wesley Kieffer and JP Ruitenbeek it turned out to be new hardening items which got turned on.

When clearing the before setting in the image and then sealing the older images would update just fine. After reproducing the entire setup in my own lab I encountered the same issue as well. Opened up a VMware support case which still is being worked at.

The setup being used is VMware Horizon 7.13.1

The following article also describes how you can troubleshoot the internal VM which is being used for the cloning process: Troubleshooting Instant Clones in the Internal VM Debug Mode

And for some more information regarding Kerberos armoring see What’s New in Kerberos Authentication | Microsoft Docs and Compound Authentication and Active Directory Domain Services claims in Active Directory Federation Services | Microsoft Docs

Hope it helps!

Notes from the field: Another cannot complete your request with Citrix FAS

We’ve all seen it time and time again some misconfiguration with Citrix StoreFront and/or Citrix FAS and you’ll be getting the cannot complete your request message in your screen. Digging in the StoreFront logs and you’ll be seeing the most interesting messages of error kind in which you would think am I a rocket professor?

My story for this certain scenario would be a CVAD deployment integrated with FAS and everything working just fine with some minor bumps like adding your resources to the Windows Authorization Access Group and magic occurs things start to work. See Cannot Complete Your Request Error only occurs to certain users connecting from ADC with Azure MFA over to Storefront ( for the fun of it and it’s buddy Common Resolutions to “Cannot Complete Your Request” Error when connecting directly to StoreFront Server (

Ok well this works! Happy customer, happy consultant. And after some time of testing the customer started to migrate existing users to this solution… And stuff didn’t work.. The same error as described in the article would occur and well not so happy customer and consultant now. Troubleshooted this and what the hell new users don’t have this problem.. only existing users! Euhm.. okay.. after some more discussion with the customer it was pointed out that this domain has been alive for a while like NT time while and upgraded to the latest and greatest Windows Server 2019.

This triggered me and after some searching came across Apps and APIs require access – Windows Server | Microsoft Docs which explained the truth! We are missing stuff. I did a compare of the groups “Pre-Windows 2000 Compatible Access” and “Windows Authorization Access Group” of the customer with my own and even a brand new test setup and there the following was missing:

Seems like upgrading a domain time and time again stuff won’t get added. After adding these objects all began to work and even the manual added resources don’t need to be in there like the CVAD servers, users object.

Hope it helps!

Notes from the field: Citrix FAS request not supported

On a recent Citrix FAS deployment I’ve encountered the following error: “Request not supported” when logging in to a published application or desktop.
Article explains that re-enrollment of the domain controller authentication template or another custom template for Kerberos usage should resolve the error.

A little bit of a background on the environment, an already working Microsoft ADCS environment was in play and in use for other services. From a design/security perspective it was designed that two dedicated Microsoft ADCS servers would be used and two Citrix FAS servers connecting these new servers. The setup was working as expected but only above error would keep coming when trying to access an application or desktop.

We tried re-enrolling the domain controller authentication certificate and this didn’t do the trick, then we decided to let the Domain Controllers get the certificate from the new dedicated Microsoft ADCS servers for Citrix FAS and this did do the trick but with a side effect the chain is changed and other services would be negatively impacted so a rollback was needed.

With this information a Microsoft support case was created and ultimately they confirmed that what is mentioned in the Citrix support article should do the trick. Ok we got confirmation and yes it indeed does work when using the new ADCS servers but the issue of the original ADCS environment was still a mystery.

So next up we decided to repoint the Citrix FAS servers to the existing Microsoft ADCS server to root out any chain or other issues that might be in play. The result was exactly the same and a not supported request as the end result.

Digging deeper in the Microsoft ADCS environment it was after checking the “NTAuthCertificates” store that the existing server wasn’t there and the new servers were. This explained the smartcard logon not working when using the existing environment because an requirement for smartcard logon is that the “NTAuthCertificates” store has the issuing certificate authority propagated. After adding the certificate and waiting for replication and a reboot everything was working as expected, also when moving to the new Microsoft ADCS environment for certificate issuing.

See the following screenshot of the Enterprise PKI snap in MMC in which you can check and/or add the missing certificate:

See the following articles for extra information:

Notes from the lab: Windows firewall profile not correct after reboot

Just thought of leaving a quick win here. Did you ever had the firewall profile of Windows not correctly mapped after reboots etc.?

This is because after a reboot the Domain Controllers put it in e.g. public profile and this will get passed on to other servers as well. This will effect in not being able to manage machines because of firewall blocks etc.

Solution is to restart the “Network Location Awareness” service and dependent “Network List Service”.
This will reset it to domain profile and after reboots of the other machines which have this it will be updated to domain profile as well. Or restart the service as above that will also do the trick.

Hope it helps!


Well after migrating to Windows Server 2022 in my homelab the above will not work anymore. Appears the restarting of the NLA service has changed. After some digging around came across the following: Domain Controller thinks its on a Public Network

My working scenario is putting it a delayed start and adding domain services dependency on the NLA service with DNS and NTDS.

Notes from the field: The unexplained Outlook pop-up

Quite recently I’ve had an interesting troubleshoot at a customer. The problem was at first that there was an issue in the newly build Exchange 2019 environment that Outlook clients would open up and ask for credentials in a domain joined environment, so the SSO part of WIA isn’t working and it “seemed” to work after you would put in credentials.

Long story short support case at Microsoft was in play and after some weeks of log troubleshooting no results and a standstill for the customers migration project.

Drilldown to the issue at hand it seemed that the Exchange solution wasn’t working correctly and it was decided to uninstall the software and clean-up the entire setup and do a fresh redeploy. The engineer already repaired some ADDS inconsistencies which perhaps could be an issue but that was not the case.

At this time I got involved because the uninstall wasn’t working correctly on the last server, it kept preventing the uninstall with still some arbitrary mailboxes present and an old hardcoded OAB reference which couldn’t get removed. I’ve also had this kind of behavior with the arbitrary mailboxes on a Exchange 2016 solution and a reboot would resolve the blocking issues, the entities will get populated again and afterwards you could remove them accordingly. That was the solution here as well until the point of the OAB entry we had to delete that one through ADSIEDIT.

Ok.. all is well again and Exchange 2019 is completely removed and a redeploy was the next item. Exchange got redeployed, basic no fuzz and behavior of the client seemed to improve.. well no it came back and the outlook prompts and disconnects were reoccurring after some time again.

Next item was to strip stuff even further, we put on some scenario’s like lets do a complete redeploy of ADDS etc. which would mean a lot of work. So we tried to simulate it in separate lab environments to reproduce the issue and there we found out no issues at all, SSO was working out of the box and things started to point through customization of some sorts or other external factors.

We’ve landed on the point that perhaps the forest trust would be an issue, that was our last item to troubleshoot. There was a full forest trust in place for the migration/transition to the new network which is being used accordingly for resources etc. This was also something we implemented in both lab environments and never had any issues with. Well here comes the kicker… we’ve disabled the trust and the issues were instantly gone!

Ok. We have our little friend and are going to focus on that, it turned out that the name suffix routing enabled of the domain was giving issues, very strange because they are not overlapping of any sorts. It “seemed” all ok from a configuration point of perspective. We focused in on everything that could be an issue and ultimately came to the point that the NETBIOS name and FQDN of ADDS where the same with a dot in it e.g. domain.local for them both.. Right this isn’t something that you can setup anytime soon from Server 2019 through Windows 2000 and is basically not supported or advised to use, this was the case in Windows NT4 but further on no go at all.

Recap of the whole situation we have our workaround for the customer, but the root cause with NETBIOS and a dot in its setup isn’t going away. The migration is focused to move it all as soon as it can and then kill the trust and any connections to the old forest/domain which was giving all this grief.

I’ve had an splendid troubleshoot with the engineer who’s a wizard in ADDS, be sure to connect or follow him on LinkedIn.

Christiaan Ploeger