The Secure Boot update failed. Unknown HResult Error code: 0x800700c1.

[resistencia]

I think it's a Windows error. What version of Windows 11 do you have? The link you sent me affects Windows 11 version 23H2. Error 0x800700c1 indicates a Windows update failure.

[movoodoo]

@Resistencia 

Windows 11 24H2.

I completely reinstalled Windows. No result.

I have no problems or errors with Windows updates.
So it's unlikely to be a problem with Windows updates.

Moreover, I found several similar problems without solutions in this community.

https://h30434.www3.hp.com/t5/Notebook-Boot-and-Lockup/The-Secure-Boot-update-failed-to-update-a-Sec...

https://h30434.www3.hp.com/t5/Notebook-Operating-System-and-Recovery/The-Secure-Boot-update-failed-t...

https://h30434.www3.hp.com/t5/Notebook-Operating-System-and-Recovery/Wrong-value-for-SecureBoot-s-Av...

[resistencia]

Check the Windows update history to see if you have the following package installed : KB5036210

KB5036210: Deploying Windows UEFI CA 2023 certificate to Secure Boot Allowed Signature Database (DB)...

1. To verify that the Secure Boot DB update was successful, open a PowerShell console and ensure that PowerShell is running as an administrator before running the following command: [System.Text.Encoding]::ASCII.GetString((Get-SecureBootUEFI db).bytes) -match ‘Windows UEFI CA 2023’

It should return the value True, otherwise it is not installed.

[movoodoo]

@Resistencia 

We've discussed this before.
I almost started with this.

[System.Text.Encoding]::ASCII.GetString((Get-SecureBootUEFI db).bytes) -match ‘Windows UEFI CA 2023’
False

I installed all the Windows updates. Everything was OK, without any errors.

But I got this error:

"The Secure Boot update failed to update a Secure Boot variable with error Unknown HResult Error code: 0x800700c1. For more information, please see https://go.microsoft.com/fwlink/?linkid=2169931"

And when I check:

[System.Text.Encoding]::ASCII.GetString((Get-SecureBootUEFI db).bytes) -match ‘Windows UEFI CA 2023’

I got:

False

I reinstalled Windows.

Original Install Date: 6/23/2025, 12:02:14 AM

The new system should already include these updates (KB5036210), right?

(https://support.microsoft.com/en-us/topic/kb5036210-deploying-windows-uefi-ca-2023-certificate-to-se...

"Windows updates released on and after February 13, 2024 include the ability to apply the Windows UEFI CA 2023 certificate to UEFI Secure Boot Allowed Signature Database (DB). Updating the DB will enable devices to receive future boot loader updates that are included in monthly updates.")

But even after reinstalling the system, I get the same error:

"The Secure Boot update failed to update a Secure Boot variable with error Unknown HResult Error code: 0x800700c1. For more information, please see https://go.microsoft.com/fwlink/?linkid=2169931"

And:

[System.Text.Encoding]::ASCII.GetString((Get-SecureBootUEFI db).bytes) -match ‘Windows UEFI CA 2023’
False

[resistencia]

This is a question for Microsoft to find out why it is not updating. The only thing I can suggest is to reinstall Windows, but delete the previous partitions on the disk where many firmware updates are stored, and try again.