Has anyone else seen domain trust or secure-channel problems after installing KB5124008 on a Windows 11 25H2 client? In testing with Windows Server 2019 domain controllers that had not yet been patched, the client accepted domain credentials after reboot, but Test-ComputerSecureChannel returned false and reported that the secure channel was broken. At the same time, nltest /sc_query:domain showed a successful connection to the domain controller. Running Test-ComputerSecureChannel -Repair restored the channel and subsequent checks returned True. I'm trying to determine whether this is a real update-related issue or an inconsistent diagnostic result before deploying the update more broadly.
2 Answers
The different results suggest the Netlogon connection was still working while PowerShell detected a problem with the computer account’s secure channel. I’d compare the client and domain-controller patch levels, then monitor more machines before concluding that the update consistently breaks trust. A repair command can restore the channel, but it’s worth checking event logs and validating whether the problem returns after another reboot.
I saw the same behavior on a Windows 11 25H2 machine after installing KB5124008. The client could still authenticate against our unpatched Windows Server 2019 domain controllers, and nltest /sc_query:domain reported NERR_Success, but Test-ComputerSecureChannel returned false. Running Test-ComputerSecureChannel -Repair fixed it immediately, so I’m testing additional clients to see whether the issue is widespread or just a misleading check.

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