Lost Windows activation after bios update

tuomri 0 Reputation points
2026-01-25T18:21:58.2466667+00:00

So I updated my bios yesterday, and after that I got error:

"We can't activate Windows on this device right now. You can try activating again later or go to the Store to buy genuine Windows. Error 0x803FABC3"

Windows was activated before bios update via my microsoft account for years.

When I click Troubleshoot, it says it isn't able to activate Windows, then I clicked "I changed hardware on this device recently" it opens Reactivate Windows, shows my PC there (I think it's old one, because it says "DESKTOP-<something>Windows 10 ProfessionalASUStek COMPUTER INC.", if I click that this is the device I'm using right now comes error that it is unable to Activate windows now try again later... what can I do? I have tried multiple times and restarted my pc, but always get the same error.

Specs:

Intel i5-8600K

GTX 1080 FTW

MSI Z370 Tomahawk

4x8GB DDR4 3200Mhz

Windows 11 Pro 24H2

OS Build number: 26100.7623

Windows for home | Windows 11 | Licensing and activation

3 answers

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  1. Neil D 33,915 Reputation points Volunteer Moderator
    2026-01-25T19:26:39.45+00:00

    As per the other answer.

    An upgrade licence cannot be used to activate Windows 11. Only an original Windows 10 licence is accepted.

    It looks like when you updated the bios it prompted the activation server to check the licence and it has been rejected.

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  2. EmilyS726 256.8K Reputation points Independent Advisor
    2026-01-25T19:08:51.8266667+00:00

    If this license was upgraded from Windows 7 or 8 to 10, then to 11, the license can be voided. It is a loophole Microsoft closed not too long ago. The upgrade was meant for Windows 10 only.

    If the license is not from a Windows 7 or 8 era, try to uninstall the most recent installed BIOS and see if it helps.

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  3. AI answer

    2026-01-25T18:22:08.37+00:00

    It seems that after updating your BIOS, your Windows activation has been affected, resulting in the error code 0x803FABC3. This error typically indicates that Windows cannot verify the activation status due to hardware changes or issues with the activation servers.

    Here are some steps you can take to resolve this issue:

    1. Run the Activation Troubleshooter: Since you mentioned you already tried this, ensure you select "I changed hardware on this device recently" when prompted. This option may help you reactivate Windows using your Microsoft account.
    2. Check Your Microsoft Account: Log into your Microsoft account on the Microsoft website and check if your Windows license is linked to your account. If it is, you should be able to reactivate Windows from the troubleshooter.
    3. Use Command Prompt: Open Command Prompt as an administrator and run the following command: 
         slmgr.vbs /ato
      This command attempts to activate Windows again.
    4. Contact Microsoft Support: If the issue persists, consider reaching out to Microsoft Support for assistance. They can provide specific guidance based on your situation.
    5. Revert BIOS Settings: If possible, try reverting the BIOS settings to their previous state before the update, as this might resolve any conflicts that arose from the update.

    If none of these steps work, you may need to consider reinstalling Windows or contacting support for further assistance.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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