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How to resolve Error code 0xC004C008 (...product key was already used on another device..._

Chad Brandon 0 Reputation points
2025-12-06T05:19:03.1166667+00:00

I recently used a 25-digit RETAIL Windows product key on a Dell XPS 13 that was purchased with Ubuntu from Dell. The product key that I used to install Windows was a RETAIL key that I purchased years ago, but hadn't used.

I decided to return the computer to Dell, so I removed it from my Microsoft account's registered Devices and followed Microsoft's prompts to remove it from my account in the Microsoft Store. I ran the slmgbr.vbs commands to confirm it was recognized as a RETAIL product key and to uninstall it from the machine. I confirmed that it was removed and the device was no longer validated.

According to everything I've read from Microsoft and 3rd party tutorials, that should have freed up this product key to be used on the next computer. However...

Now, when I try to use this product key on my new computer, I get error code 0xC004C008... "We can't activate Windows on this device because the product key was already used on another device..."

Is Microsoft really only allowing a key to be used on 1 device ever? That seems absolutely ridiculous.

What am I missing here? How can I get this key to work again and avoid this issue in the future?

To add insult to injury, I had used another RETAIL product key on a Windows virtual machine in Parallels that I had to wipe for fear of malware on MacOS. That product key is also being blocked from use via the same error. How does one even get help from MS these days? Argh.

Windows for home | Windows 11 | Licensing and activation
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  1. Q&A Assist
    2025-12-06T05:19:18.85+00:00
    AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

    The error code 0xC004C008 indicates that the activation server determined that the specified product key could not be used, often because it has already been activated on another device. In your case, it seems that even after following the steps to remove the product key from your previous device, the activation server still recognizes it as being in use.

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

    1. Contact Microsoft Support: Since you have already removed the product key from your Microsoft account and the device, the best course of action is to contact Microsoft Licensing Activation Centers. They can check the status of your product key and help you resolve any issues related to its activation.
    2. Check for Multiple Activations: If you used the product key on multiple devices or virtual machines, the key may have reached its activation limit. Microsoft allows a limited number of activations for retail keys, so confirming that you haven’t exceeded this limit is essential.
    3. Consider Using a Different Key: If you have another valid product key, you might want to try using that instead to avoid further complications.

    It's important to note that while retail keys are generally transferable, there can be complications with activation if the key is still associated with another device in Microsoft's records.

    For future installations, ensure that you properly deactivate or remove the product key from any device before attempting to use it on a new one to avoid similar issues.

    References:

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