Help reactivating Windows 11 after changing encryption keys.

Question

Help reactivating Windows 11 after changing encryption keys.

David Linnard 0

I need manually reactivating Windows. I recently began seeing the “Activate Windows” message on my desktop even though this device has been activated for years.

In my Microsoft account’s device list, my PC now appears twice, showing two entries for the same hardware. This duplication seems to have occurred while I was trying to get device encryption working. Device encryption was never successfully enabled, but during troubleshooting my encryption keys were reset in the BIOS. After that reset, Windows began reporting that it was no longer activated.

My Windows license is a retail license, originally purchased many years ago (dating back to the XP era) and carried forward through multiple upgrades and several motherboard replacements over time. Despite these hardware changes, the license has always activated correctly until this recent issue.

I attempted to activate using the Installation ID, but I am not getting anywhere with the Product Activation Portal, and offline phone activation seems not to be supported. Therefore, I am unable to complete activation through normal methods. Please help.

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3 answers

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Answer 1

Emma1-N 13,410 Microsoft External Staff Moderator

Welcome David Linnard,

Thank you for providing the detailed background. Since your Windows installation was previously activated for years and the issue started after changes related to device encryption and BIOS key reset, I would like to gather a little more information before suggesting further steps.

Could you please confirm the following:

Open Settings > System > Activation and tell us the exact activation status shown there. Does it say "Windows is not activated" and is there an error code (for example, 0xC004F211, 0xC004F213, etc.)?
Is the Microsoft account currently signed in under Settings > Accounts > Your info the same Microsoft account that previously held the digital license?
Have you already run the Activation Troubleshooter by going to Settings > System > Activation > Troubleshoot? If so, what result did it report?

In the meantime, please try this quick check:

Open Settings > System > Activation
Select Troubleshoot
If available, choose I changed hardware on this device recently
Sign in with your Microsoft account and select the correct device from the list

The duplicate device entries in the Microsoft account device list do not necessarily indicate a licensing problem by themselves, but the activation error code and troubleshooter result will help determine whether Windows still recognizes the existing digital license.

For reference, see Microsoft's activation guidance: https://support.microsoft.com/windows/activate-windows-c39005d4-95ee-b91e-b399-2820fda32227

Looking forward to your update.

David Linnard 0 Reputation points

2026-09-29T20:44:08.55+00:00

Thank you for responding Emm1-N:

System>Activation Yes. It says Windows is not activated. Also "We can't activate Windows on this device right now".... 0x803FABC3

Yes. I have only had one Microsoft account for years and this computer is displayed twice under my account devices, apparently the current image and the previous one. Both computer descriptions have the same name, mother board model and RAM. The OS that was first migrated from Win 10 shows OS Edition Windows Core Version 2009 Build 10.0.26200.9457. The version that I am using now, after the key problem shows Windows 11 Home Version 2009 Build 10.0.26200.8875 or maybe vice versa, I can't be sure which is which.

The trouble shooter said "We weren't able to activate Windows on this device. Contact support to get help." Clicking the button returned: "Unable to activate Windows We can’t find any devices linked to your Microsoft account that can be used for reactivating the device you’re using right now. Make sure you’re signed in with the same Microsoft account you linked to the Windows 10 digital license on this device or try again later."
Emma1-N 13,410 Reputation points Microsoft External Staff Moderator

2026-10-01T04:14:49.6566667+00:00

Hello David Linnard,

Since Windows cannot find a qualifying device linked to your Microsoft account for reactivation, this will require review by Microsoft Support, as community members do not have access to activation records.

Please follow the steps Neil D outlined to contact Microsoft Support through the Get Help app.

Thank you for your understanding.

Answer 2

Neil D 34,350 Volunteer Moderator

If the licence for Windows 11 originated from part of the free upgrade to Windows 10 from Windows 7/8 those licences are no longer allowed to activate Windows 11.

Microsoft have blocked them by making changes to activation in 2023. What probably caused the activation check is changes to the bios.

You will no longer be able to use an old licence for windows 11.

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Answer 3

Neil D 34,350 Volunteer Moderator

An old licence cannot be used to activate Windows 11 anymore. The two instances you see just list the systems that have been registered and don't confirm a valid licence.

To confirm you will need to contact Microsoft Support directly. Use the Get Help app in widows and search the phrase billing. Then select Contact Support at the bottom of the window. The there will be a couple more filters to select but after that you will see the option to Chat with a support agent in your browser.

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