KB5120249: Windows 10 Version 21H2 Security Update (August 2026)

Devices with an unrecommended BitLocker Group Policy configuration might be required to enter their BitLocker recovery key

Symptoms

Some devices with an unrecommended BitLocker Group Policy configuration might be required to enter their BitLocker recovery key on the first restart after installing this update.

This issue only affects a limited number of systems in which ALL the following conditions are true. These conditions are unlikely to be found on personal devices not managed by IT departments.

BitLocker is enabled on the OS drive.

The Group Policy Configure TPM platform validation profile for native UEFI firmware configurations is configured, and PCR7 is included in the validation profile (or the equivalent registry key is set manually).

System Information (msinfo32.exe) reports Secure Boot State PCR7 Binding as Not Possible .

The Windows UEFI CA 2023 certificate is present in the device’s Secure Boot Signature Database (DB), making the device eligible for the 2023‑signed Windows Boot Manager to be made the default.

The device is not already running the 2023-signed Windows Boot Manager.

In this scenario, the BitLocker recovery key only needs to be entered once -- subsequent restarts will not trigger a BitLocker recovery screen, as long as the group policy configuration remains unchanged. For help finding your BitLocker recovery key, see [Find your BitLocker recovery key](https://support.microsoft.com/Windows/Security/Encryption/find-your-bitlocker-recovery-key).

Enterprises are recommended to audit their BitLocker group policies for explicit PCR7 inclusion and check msinfo32.exe for their PCR7 binding status before installing this update.

Resolution

This issue is addressed in update KB5122878 . After installing update KB5122878, devices with this incompatible group policy configuration are prevented from installing the 2023-signed Windows Boot Manager. If your device was impacted, Event ID 1032 will appear in the System event log when installing Windows updates: "The Secure Boot update Boot Manager (2023) was not applied due to a known incompatibility with the current BitLocker configuration."

If you receive Event ID 1032 , Microsoft strongly recommends removing the Group Policy configuration before installing updates so that you can install the 2023-signed Windows Boot Manager and continue to receive the latest Secure Boot protection.

Remove the Group Policy configuration before installing the update (Recommended)

Open Group Policy Editor (gpedit.msc) or your Group Policy Management Console.

Navigate to: Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives .

Set Configure TPM platform validation profile for native UEFI firmware configurations to Not Configured .

Run the following command on affected devices to propagate the policy change: gpupdate /force

Run the following command to suspend BitLocker (if BitLocker is enabled on the C: drive): manage-bde -protectors -disable C:

Run the following command to resume BitLocker (if BitLocker is enabled on the C: drive): manage-bde -protectors -enable C:

This updates the BitLocker bindings to use the Windows-selected default PCR profile.

If you do not wish to remove this Group Policy configuration, you can install the new Windows Boot Manager by temporarily suspending BitLocker and installing the Secure Boot update. To do this:

Run the following command to suspend BitLocker (if BitLocker is enabled on the C: drive): manage-bde -protectors -disable C:

Run the following command: Start-ScheduledTask -TaskName \\Microsoft\\Windows\\PI\\Secure-Boot-Update

Restart the device.

Once the new Windows Boot Manager is successfully installed, enable BitLocker by running the command: manage-bde -protectors -enable C: