error code 0xC004C008

Question

Cannot reactivate Windows using a retail key. I had to reinstall, and now it says it's already activated on another device. It isn't. This is the same machine, and NO other machines are using this retail license key.

Answer 1

Hi Donovan,

Windows activation checks your hardware profile against what’s stored on Microsoft’s servers. After a clean reinstall or major hardware change (like motherboard replacement), the system may think it’s a “different” computer. Retail keys are flexible, but they still trigger this error if the activation servers detect multiple activations.

 

What you can do:

Run the Activation Troubleshooter

Go to Settings → Update & Security → Activation.

If you see Troubleshoot, click it.

Sign in with the Microsoft account linked to your license.

Choose I changed hardware on this device recently and select your current device.

Activate by Phone

Press Win + R, type slui 4, and hit Enter.

Pick your country, call the toll-free number, and provide the installation ID.

Enter the confirmation ID they give you.

Contact Microsoft Support

If the above doesn’t work, explain that this is the same machine and your retail key isn’t used elsewhere. They can manually verify and reactivate.

 

Let me know how it goes, Happy to help!