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Windows 11 won't activate after OS Repair, Error messge: Unable to activate Windows

Ruben 5 Reputation points
2025-12-11T16:31:27.9333333+00:00

Hello,

After a recent update, my hard drive became corrupted. The computer was working fine before the update, but after rebooting, I received the error: “No bootable device found.”

I attempted to fix the boot configuration, but nothing worked. I then repaired the OS by reinstalling Windows while keeping my data. However, after the installation, Windows will not activate.

My original product was Windows 10 Pro. On the activation page, I clicked Troubleshoot, then selected I changed hardware on this device recently, and received this message:

Unable to activate Windows We can't reactivate Windows as our servers aren't available right now. Wait for a few minutes or try adding your Microsoft account again.

Additionally, my Microsoft account no longer shows this PC as one of my devices.

Could you please advise on how to resolve this issue?

Thank you,

Windows for home | Windows 11 | Licensing and activation
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  1. Rez 12,905 Reputation points Independent Advisor
    2025-12-11T17:06:58.5233333+00:00

    Hi Ruben, I understand how stressful it can be when things don’t work after a repair. What’s happening is that your digital license, which was tied to your old Windows installation, isn’t automatically linking to the new one because the reinstall changed system identifiers. The quickest fix is to make sure your Microsoft account is added under Settings → Accounts, then go to Settings → System → Activation and run the Troubleshooter, choosing “I changed hardware on this device recently.” If the servers were down earlier, give it some time and try again. Also, confirm you installed the same edition as before, Windows 11 Pro if you had Windows 10 Pro. If your PC still doesn’t show under your Microsoft account, re-add it and restart. Can you check if your account is linked and if the edition matches?

  2. Rez 12,905 Reputation points Independent Advisor
    2025-12-11T17:34:06.06+00:00

    That's great to hear! Feel free to upvote and accept my answer if it helped you, so other users can find solutions. 

    All the best, 

    Rez 

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  3. Rez 12,905 Reputation points Independent Advisor
    2025-12-11T17:34:44.1933333+00:00

    Have a great day.

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