Outlook LTSC 2024 shows "This feature has been disabled by your administrator" at startup after update to Build 17932.20996

Question

Outlook LTSC 2024 shows "This feature has been disabled by your administrator" at startup after update to Build 17932.20996

Zacharias Embaxter 75

Environment:

Office LTSC 2024, volume licensed, managed via Active Directory Group Policy
Enterprise environment
Connected Experiences and related privacy/sign-in settings configured via GPO

Symptom: Since updating Office LTSC 2024 to Version 2408, Build 17932.20996 (released September 12, 2026, apparently an out-of-band build following the September 8, 2026 Patch Tuesday release, Build 17932.20976), Outlook displays the message "This feature has been disabled by your administrator" every time it starts.

Relevant configuration: The following registry value, not only, has been configured via GPO for a long time and has never caused this behavior before:

HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\common\signin
SignInOptions = 3 (DWORD)

This policy is intended to block Office sign-in entirely and has been working as expected for a long time. It only started causing the startup error message after installing the above-mentioned update. If i delete this Key, the Signin Windows popup after Outlook starts.

0 comments

Answer recommended by moderator

Zacharias Embaxter 75

Solution found under:

https://learn.microsoft.com/en-gb/answers/questions/5590921/running-office-2024-ltsc-outlook-has-begun-prompti

The thread mentions the entry “[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity] ‘EnableADAL’=dword:00000000”. However, it also works under “[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Common\Identity] ”EnableADAL=dword:00000000". This entry, however, is not found in the current ADMX files dated August 10, 2026, and therefore cannot be configured via gpedit.msc.

The thread above is from October 2025. We can only speculate as to why this is happening now.

Thanks all for your help.

JeseminQH 600 Reputation points Independent Advisor

2026-09-16T04:37:52.78+00:00

Hi @Zacharias Embaxter ,

I’m glad you found a workaround that fixed the issue. As similar behavior was discussed in October 2025 and appears to be occurring again in 2026 on Build 17932.20976, I suggest submitting feedback through the Outlook app.

While submitting feedback does not guarantee an individual response or an immediate fix, it can help collect reports and bring recurring issues affecting the current build to the attention of the relevant product team.

Thank you for your patience and understanding

2 additional answers

Your answer

JeseminQH 600 Reputation points Independent Advisor

2026-09-16T04:37:52.78+00:00

Hi @Zacharias Embaxter ,

I’m glad you found a workaround that fixed the issue. As similar behavior was discussed in October 2025 and appears to be occurring again in 2026 on Build 17932.20976, I suggest submitting feedback through the Outlook app.

While submitting feedback does not guarantee an individual response or an immediate fix, it can help collect reports and bring recurring issues affecting the current build to the attention of the relevant product team.

Thank you for your patience and understanding

Answer 1

JeseminQH 600 Independent Advisor

Hi @Zacharias Embaxter ,

If permitted by your organization’s sign-in requirements, you may also test the following registry value with 1 or 2 for one affected user:

HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\common\signin  
SignInOptions = 3 (DWORD)

Please test each value separately, restart Outlook, and check whether the behavior changes. Since this value is managed through Group Policy, your administrator may need to make the temporary change. If there is no difference, please restore the original value of 3.

Disclaimer: Generally, modifying registry subkeys or work group is intended for advanced users, administrators, and IT Professionals. It can help fix some problems, however, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For further protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click How to back up and restore the registry in Windows to view the article.

Since this is an enterprise environment, could you also confirm whether the issue affects all users who receive the same Group Policy settings, or only specific users or devices?

Additionally, please try starting Outlook in Safe Mode by pressing Windows key + R, entering the following command, and selecting OK: outlook.exe /safe

Safe Mode starts Outlook without most add-ins and custom settings. If the message does not appear in Safe Mode, an add-in or Outlook customization may be contributing to the issue. Open Outlook in safe mode

If the issue continues, please try creating a new Outlook profile by following the steps in this official Microsoft Support article: Create a profile in classic Outlook for Windows. This will help determine whether the issue is related to the existing Outlook profile.

Feel free to share the requested details when convenient. I look forward to hearing from you.

Zacharias Embaxter 75 Reputation points

2026-09-14T10:07:47.4366667+00:00

Thanks for your fast reply.

When I set the value to 1 or 2, I get a prompt to sign in to Microsoft. Creating a new Outlook profile doesn't solve the problem either. The problem has only been occurring since the update. Even if only the update from September 8, 2026, with version number 17932.20976, is installed, the problem still occurs. The problem occurs on all clients that have installed the September update.
Zacharias Embaxter 75 Reputation points

2026-09-14T11:23:22.88+00:00

Even if all policy settings except for the “signinoptions” policy are removed, the problem persists.
Zacharias Embaxter 75 Reputation points

2026-09-14T13:34:38.2033333+00:00

My fault. I mean 20976 an 20996
JeseminQH 600 Reputation points Independent Advisor

2026-09-15T05:59:57.42+00:00

Hi @Zacharias Embaxter ,

Thank you for providing the test results.

Since the behavior continues with SignInOptions set to 1 or 2, and creating a new Outlook profile did not resolve it, further investigation may be required. You also noted that the behavior occurs across clients that installed the September 2026 update, including Version 2408, Build 17932.20976.

At this stage, I suggest raising a support ticket with Microsoft Support for further investigation. A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to resolve the problem. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis.

To raise a support ticket, sign in to the Microsoft 365 admin center with an administrator account, select Help > Help & Support.

For more details, please refer to: Get support - Microsoft 365 admin

When submitting the request, include the affected build number, the SignInOptions policy configuration, the exact message displayed, the scope of affected clients, and the troubleshooting already performed.

If you’re unsure who the Global Admin is within your organization, you can find guidance on locating them here: How do I find my Microsoft 365 admin?

Note: If you’re an end-user, please coordinate with your Office 365 Global Administrator to handle these step

Before submitting the request, make sure Support Assistant is turned off. Some customers have reported that the Contact Support option may not appear while Support Assistant is enabled.

As shown in the screenshot, switch Support Assistant to Off, and then enter a description of the issue. The Contact Support button should then appear, allowing you to submit the request.

I apologize for not being able to assist further. As a fellow user in this community, I do not have the authority, access, or internal diagnostic tools required to investigate this issue. If the behavior is related to a backend service or requires internal investigation, Microsoft Support would be best placed to assist and raising a support ticket will help make them aware that the behavior is occurring with the current version and allow them to investigate it further.

Answer 2

Lionel TRAVERSE 0 MVP

Hello,

Can you try disabling ADAL in Office 2024 by using the following registry key and restart Outlook :

HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\EnableADAL=dword:00000000

Best regards,

Lionel TRAVERSE

Lionel TRAVERSE 0 Reputation points MVP

2026-09-16T06:35:29.0366667+00:00

On y side, this registry permits to resolve also the issue when Outlook want to "add service" when it starts.

Best

Lionel