corparte wifi connectvity issue

Question

corparte wifi connectvity issue

Dharmendra Singh2 0

after update the latest patch oct month, the corparte wifi not connect in the domain machine. please provide the solution urgent basis.

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3 answers

Your answer

Answer 1

If the corporate Wi‑Fi uses PEAP‑MSCHAPv2 or EAP‑MSCHAPv2 and NTLM Event ID 4025 is present, temporarily set BlockNtlmv1SSO to 0 on affected machines, then migrate the wireless authentication to certificate-based EAP‑TLS.

KB5127648 changed the default from Audit to Enforce mode on eligible devices, which can block single sign-on for corporate Wi‑Fi using MS‑CHAPv2. This specifically applies when Credential Guard is disabled and the BlockNtlmv1SSO value is absent. ^1^

Immediate recovery

Try connecting by entering the domain credentials manually, rather than using saved credentials or automatic single sign-on. Manual credential entry continues to work in Enforce mode. ^2^
On one affected test machine, open: Event Viewer → Applications and Services Logs → Microsoft → Windows → NTLM → Operational Attempt the Wi‑Fi connection and look for:
- Event ID 4025, Error: an attempt to use NTLMv1-derived SSO credentials was blocked.
- Event ID 4024, Warning: the same authentication was audited but allowed.
If Event ID 4025 appears, deploy the following temporary exception from an elevated Command Prompt:

reg add "HKLM\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0" ^
 /v BlockNtlmv1SSO /t REG_DWORD /d 0 /f

wevtutil qe Microsoft-Windows-NTLM/Operational ^
 /q:"*[System[(EventID=4024 or EventID=4025)]]" /c:10 /f:text

A restart is not required for this registry change. Reconnect to the corporate Wi‑Fi and confirm that authentication succeeds and Event ID 4024, rather than 4025, is recorded. ^2^

Security warning: BlockNtlmv1SSO=0 reduces the protection provided by Enforce mode. Deploy it only to affected devices as a scoped, temporary exception through Group Policy, Intune, or your normal endpoint-management system.

Do not remove KB5127648 across the environment as the primary fix; it is a security update, and Microsoft’s published 26H2 known-issues page does not currently list corporate Wi‑Fi as a confirmed general defect. ^3^

Permanent resolution

Change the RADIUS/NPS and wireless profile from password-based PEAP‑MSCHAPv2 or EAP‑MSCHAPv2 to certificate-based EAP‑TLS or PEAP‑TLS. Microsoft recommends certificate-based authentication because MS‑CHAPv2-based Wi‑Fi is affected by NTLMv1-related protections. ^4^

After the certificate-based profile is deployed and validated:

reg add "HKLM\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0" ^
 /v BlockNtlmv1SSO /t REG_DWORD /d 1 /f

Test with a pilot group before broad deployment.

If Event ID 4025 is absent

The NTLM enforcement mitigation does not apply. Collect the failure immediately after reproducing it from:

Event Viewer → Applications and Services Logs → Microsoft → Windows → WLAN-AutoConfig
Event Viewer → Applications and Services Logs → Microsoft → Windows → NDIS
The RADIUS/NPS authentication logs

Check whether the Wi‑Fi adapter connects to a phone hotspot. If hotspots work but corporate Wi‑Fi fails, focus on the 802.1X profile, authentication method, certificates, and RADIUS rejection reason rather than reinstalling the wireless adapter.

References

Answer 2

Dharmendra Singh2 0

we have try all of this but issue not resolved till now.

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Answer 3

Welcome to Microsoft Q&A!

Thank you for the update and for taking the time to work through the troubleshooting already suggested.

I am sorry to hear that the corporate Wi-Fi is still unavailable after those steps.

Explanation

The October 13, 2026 Windows security update includes authentication-related security changes that can affect environments using MS-CHAPv2. The previously suggested BlockNtlmv1SSO=0 setting is intended as a temporary mitigation for the specific scenario in which NTLMv1-derived Single Sign-On credentials are being blocked.

Since you have already tested that mitigation and the corporate Wi-Fi still does not connect, I would not recommend continuing to change the BlockNtlmv1SSO setting or making additional security-related registry changes without first confirming the actual authentication failure.

In other words, although the issue appeared after the October update, the timing alone does not establish that the update is the direct cause.

Likely cause

At this stage, the behavior should be investigated as an environment-specific 802.1X authentication failure.

Microsoft's current Windows 11, version 26H2 release-health information does not list corporate Wi-Fi connectivity as a general known issue. Therefore, the next investigation needs to determine where authentication is failing between the affected Windows client and your organization's Wi-Fi authentication infrastructure.

Recommended next step

Because the documented NTLM mitigation has not resolved the problem, I would avoid uninstalling the security update or applying additional registry workarounds simply to test whether the behavior changes.

Instead, I recommend opening a Microsoft Support for Business case and providing the authentication logs from an affected device together with the corresponding RADIUS/NPS information.

I appreciate that opening a support case may feel like an additional step, especially after you have already spent considerable time troubleshooting this issue. I am not suggesting this because there are no further troubleshooting possibilities. Rather, the next stage requires correlation between information from the affected Windows device and your organization's authentication infrastructure.

Microsoft Q&A is a community-based support forum, and I cannot directly examine your organization's RADIUS/NPS configuration or perform the deeper diagnostic investigation needed to identify exactly where the 802.1X authentication exchange is failing. Continuing to suggest registry changes here could therefore add risk without giving you a reliable root-cause determination.

For that reason, a Microsoft Support case would be the safest and most effective next step, particularly because this is affecting a corporate environment.

Before opening the support case, reproduce the Wi-Fi failure on one affected computer and collect the following information while the failure is occurring:

WLAN-AutoConfig event logs from the affected Windows device
Microsoft-Windows-NTLM/Operational event logs
The corresponding RADIUS/NPS authentication log
Windows edition and version
OS build number
Installed October KB
Corporate Wi-Fi authentication method, such as PEAP-MSCHAPv2 or EAP-MSCHAPv2
The exact error displayed when the Wi-Fi connection fails
The result when the user manually enters the domain credentials instead of relying on automatic authentication

Providing these details with the support request will give Microsoft Support and your network team a much stronger starting point for determining whether the failure is occurring on the Windows client side or during the RADIUS/NPS authentication process.

I completely understand that you were looking for an immediate fix. Since the documented mitigation has already been tested without success, however, I do not want to ask you to repeat the same troubleshooting or make further security changes without evidence that they apply to your environment. At this point, escalating the collected diagnostic information is the more appropriate way to move toward a reliable resolution.

I hope this helps clarify why I recommend moving to a support case at this stage.

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