KB5072033 break remote credential guard to Windows server 2025

Pierre DESTRÉE 70

We are experiencing a reproducible issue with Remote Credential Guard (RCG) when connecting from Windows 11 24H2 clients to a Windows Server 2025 RDP host. Remote Credential Guard works correctly before installing update KB5072033 on the client. Immediately after installing this update, RCG stops functioning.

The issue is fully reproducible and affects only Windows 11 24H2 clients where KB5072033 is installed. The Windows Server 2025 host has also received the December cumulative update, but this does not change the behavior: RCG still fails when the client has KB5072033 installed.

Robert Thunell 20 Reputation points

2026-01-30T10:16:42.81+00:00

Microsoft, any progress in this? it is a showstopper for Server 2025 deployment!!
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Herkt, Krzysztof 0 Reputation points

2026-04-29T08:35:33.1766667+00:00

Sadly April Updates didnt fix it either
Dawid Czyżycki 30 Reputation points

2026-05-04T11:13:21.6733333+00:00
KB5083631

not tested yet but promising :)

*

[Authentication (Kerberos)] This update improves Kerberos authentication in Remote Desktop sessions using Remote Credential Guard addressing error 0xc000009a.

--edit

KB5083631

Installed on a 25H2 Windows 11 client still doesnt fix the issue,

When remoting to Windows Server 2025 - second hop doesnt work for network drives,

When remoting to Windows Server 2022 - second hop works as expected.
Fil 0 Reputation points

2026-05-04T22:04:41.8433333+00:00

if source and target machine have got KB5083631 installed, both web sso and network share access seems fixed during my initial tests.

scenario's tested:
Windows 11 25h2 --> rdp /remoteguard to windows 11 25h2
Windows 11 24h2 --> rdp /remoteguard to windows 11 25h2.

Thank you SteveS :-p
MTG 1,261 Reputation points

2026-06-01T11:51:15.16+00:00

@Fil Yes, between Windows 11 24/25 H2, it's fixed, but for RCG to RD session hosts that run windows server 2025, it's still there since server 2025 didn't get that patch. Anybody here know why not or whether a fix is planned?
Adam Karas 0 Reputation points

2026-06-01T13:50:24.4933333+00:00

I can confirm it works from Windows 11 25H2 to Windows Server 2025 with mentioned KIR fix.

@MTG If the RD Session Host role is installed on the server, RCG must be enabled at the GPO level (client). It does not work with the mstsc.exe -remoteGuard parameter.”
MTG 1,261 Reputation points

2026-06-02T13:33:32.9933333+00:00

Hi Adam.

I can confirm it works from Windows 11 25H2 to Windows Server 2025 with mentioned KIR fix.

Now that puzzles me. That fix is active at my target server, active for months and no, we don't use /remoteguard, but have it required using GPOs. All three KIRs are enabled (for comparison, look at the screenshot, please):

Let's compare: server build is 10.0.26100.32860

Client is 10.0.26200.8457 - same for you???
Adam Karas 0 Reputation points

2026-06-02T18:35:21.9466667+00:00

Hi @MTG , I have only KIR 251003_17001 installed and enabled. My server si same build "10.0.26100.32860", and multiple W11 24/25H2 clients confirmed working. What is your error ?
MTG 1,261 Reputation points

2026-06-02T20:47:46.5433333+00:00

@Adam Karas Are you sure that you use the same client version, please share it. My error? The same as 2 years ago when all this started: Try to access a domain resource from within an RDP session that was initiated from Win11 24/25H2 on server 2025 and you'll get a reauthentication prompt immediately. No error, just the need to reauthenticate which defies the purpose of remote credential guard completely. The KIR was working, but just when Server 2025 was accessed from older OS' like Win11 23H2, it never worked for 25H2. If, like you, I only activate KIR...17001, it doesn't change a thing. Weird. Sure that you get that right? Some people RDP into already authenticated console sessions - then, logically, the problem never surfaces. So please share your client version and proceedings.
Adam Karas 0 Reputation points

2026-06-03T09:37:16.3333333+00:00

@MTG This is/was my error on WSrv 2025 (double hop). Client W11 10.0.26100.7171 or 26220.8474, both working. Ping me on email (should be visible in my MS profile), dont want to spam here, I hope I can help you, spent lot of days troubleshooting RCG issues.
MTG 1,261 Reputation points

2026-06-03T09:59:48.7166667+00:00

Thanks, same error here. However, be aware that your 26220.8474 is no stable release but a preview release and that 10.0.26100.7171 works here, too. So I wonder if you can test with a simple w11 25H2 with may update: 10.0.26200.8457
Adam Karas 0 Reputation points

2026-06-03T10:41:08.2733333+00:00

@MTG Yup, thats my personal insider preview version. I don't have clients updated with May update yet, but I don't think this update will have any effect.
MTG 1,261 Reputation points

2026-06-03T12:58:01.1533333+00:00

Just so that you understand: the versions you use have no problem. I knew that before. But that are not the stable 25H2 versions that we use. Those still have the problem when RDPing to Server 2025!
Adam Karas 0 Reputation points

2026-06-03T13:34:35.33+00:00

@MTG just tested with 26200.8390, working.
MTG 1,261 Reputation points

2026-06-03T13:38:58.8366667+00:00

Then tell me what you might be doing differently. Me and others have observed that it does not work despite the KIR being active. So my steps for reproduction are: Windows domain, join both devices, install may updates, apply KIR - broken. No other GPOs active apart from that that requires remote credential guard.

23 answers

jaltmann 61 Reputation points

2025-12-17T14:42:32.93+00:00

I would like to sincerely know why Microsoft consistently demonstrates poor QA around Remote Credential Guard with their updates. RCG should be used by every organization and as such should also have better assurance that when an update comes out, that it's not going to break core functionality that this security enhancement provides. I've personally been dealing with these issues for 2 years like a game of whack-a-mole...
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Pierre DESTRÉE 70 Reputation points

2025-12-12T10:13:49.3233333+00:00
I would also like to highlight an additional point that further confirms this is a regression introduced by KB5072033.

Before installing KB5072033 on Windows 11 24H2 clients:
- RCG worked correctly when connecting to Windows Server 2025
RCG did not work when connecting to Windows Server 2022

After installing KB5072033:

RCG no longer works with Windows Server 2025

RCG now works correctly with Windows Server 2022

This is the exact opposite behavior compared to before the update. No configuration changes were made on either the clients or the servers. The only change was the installation of KB5072033 on the Windows 11 24H2 clients.

This inversion strongly suggests that the update modifies the internal behavior of the RDP/CredSSP/Kerberos stack in a way that breaks compatibility with Windows Server 2025, even though the server is fully updated (including the December cumulative update).
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Quinnie Quoc 11,840 Reputation points Independent Advisor

2025-12-11T14:44:48.1566667+00:00

Hello Pierre DESTRÉE,

Thank you for sharing the detailed findings regarding Remote Credential Guard (RCG) behavior between Windows 11 24H2 clients and a Windows Server 2025 RDP host. Based on your description, the issue appears directly linked to the installation of update KB5072033, as RCG functions normally prior to applying this update and fails consistently afterward. At this time, the behavior you are seeing aligns with a known regression introduced in the update, and Microsoft is actively investigating the impact on RDP authentication and RCG negotiation. While the Server 2025 cumulative update does not resolve the issue, the current recommended workaround is to temporarily uninstall KB5072033 on affected clients or pause updates until a corrective patch is released.

You may also monitor the Windows Release Health dashboard for official status updates, as fixes for authentication‑related regressions are typically delivered through subsequent cumulative updates.

I hope this information helps you stabilize your environment while Microsoft works on a permanent resolution. If this guidance addresses your question, please consider clicking “Accept the Answer” so that others in the community can benefit from the findings as well.

Thank you so much!!

Best regards,

QQ.
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Pierre DESTRÉE 70 Reputation points

2025-12-12T09:51:40.0833333+00:00

Thank you for your response.

If this behavior is expected or already known internally, could you please clarify why it is not documented anywhere, including:

the Windows release health,

the Known Issues section of KB5072033,

and the "Windows 11, version 24H2 known issues and notifications" page

Remote Credential Guard is a critical security feature, and this update clearly changes its behavior in a way that breaks TGT forwarding between Windows 11 24H2 clients and Windows Server 2025, even when both sides are fully updated (including the December cumulative update on the server).

Kevin Cooke 5 Reputation points

2025-12-17T13:29:27.24+00:00

Are you able to provide a link to the known issue rollback for this? https://learn.microsoft.com/en-us/troubleshoot/windows-server/installing-updates-features-roles/known-issue-rollback
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KB5072033 break remote credential guard to Windows server 2025

KB5083631

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