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Windows Activation Error 0XC004C003

Anonymous
2025-01-26T20:48:10+00:00

I recently just built a new PC and had installed Windows 10 Pro via the media creation tool.

As for the license key itself, I had used the one I got from when I had bought an original Microsoft licensed copy.

Now I originally bought this a few years ago from when my laptop started having some issues with windows. Back then my laptop simply wouldn’t launch and would go straight into BIOS because of some issues and troubleshooting didn’t really help. Hence, I bought a brand new copy of Windows. However, later on it appeared that my laptop did eventually return to normal but the copy of windows I bought ended up getting delivered after it had sorted itself out. Which eventually left me with an unused copy of Windows 10 Pro.

Fast forward to yesterday where I had built my PC and ended using the copy of Windows which had been lying around unused for a few years. On using the USB the windows 10 pro box came with, it gave me a BSOD. No idea why and this ended up occurring multiple times which left me to install windows via the media creation tool. While installing however, I used the license key that came with the original box of Windows and during installation when it asked me to insert the license key, nothing out of the ordinary happened and Windows 10 installed itself with no problem whatsoever.

However, upon checking the activation status in settings, it showed me an error saying Windows couldn’t get activated and gave me this error (0XC004C003). I tried troubleshooting the problem but it simply said that the windows 10 pro installation couldn’t be activated. Even checking online for the same error code, I found that this code means that the activation code isn’t valid. Even though I had legitimately bought this copy of Windows a few years back. Microsoft Customer Support doesn’t seem to help very much and on trying to call one of the support numbers, the AI helpline just doesn’t help at all.

Does anyone happen to know how I can fix this problem? I really don’t want to have to buy a new copy of Windows or reinstall the entire thing again.

Windows for home | Windows 10 | Licensing and activation

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  1. Francisco Montilla 30,635 Reputation points Independent Advisor
    2025-01-27T20:22:26+00:00

    Hi Mahad,

    Let's try a last thing to figure out the issue. If this does not work, I will reroute your question so you can get direct support with Microsoft.

    Please take a screenshot of the dialog that pops up when using the following command:

    slmgr.vbs /dlv

    Since your key has never been used before, It should work even if it's an OEM key. I'm not sure if unused keys do expire actually.

    Let's try this, I hope we can solve it before doing more hops to the support team. :)

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  2. Anonymous
    2025-01-27T20:08:02+00:00

    Hello again Francisco,

    No worries for the late reply, I apologise for the delay on my part as well.

    I tried the methods you suggested, but unfortunately to no avail.

    As for the Microsoft account method, I switched my account to a Microsoft account login, but I’m afraid it didn’t work.

    As for the “slui 4” method, I’m afraid upon pressing enter, no screen appeared whatsoever.

    However, as for the last method you recommended, the first part worked upon using the “slmgr /ipk (product key)” but on using the second command “slmgr /ato” it returned another error “(0xC004C003) - the activation server determined the specified product key is blocked”.

    Any suggestions on what to do from here?

    Thanks for the help so far though Francisco

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  3. Francisco Montilla 30,635 Reputation points Independent Advisor
    2025-01-27T14:32:26+00:00

    Hi there,

    I apologize for the delay in responding and truly appreciate your patience. This is a public forum, and as a fellow user, I do my best to reply as quickly as possible with helpful information. I’m here to assist you and work together on a solution.

    First, please make sure you are signed in with your Microsoft account. Open Settings, select Accounts, then check if you see “Sign in with a Microsoft account” or “Change account settings”. Sometimes a product key is tied to your Microsoft account, and signing in can automatically activate Windows if that’s the case.

    Next, try the phone activation method. Press Windows + R, type "slui 4", and press Enter. Select your country or region, then call the provided phone number and follow the automated prompts. You’ll provide your Installation ID and receive a Confirmation ID to enter for activation.

    If no success, re-enter the product key using an elevated Command Prompt or PowerShell:

    • Right-click the Start button, select Command Prompt (Admin) or Windows PowerShell (Admin).
    • Type "slmgr /ipk YourProductKey" (replace YourProductKey with the actual 25-digit key) and press Enter.
    • Type "slmgr /ato" to attempt activation.

    Also, confirm that you have a valid retail key rather than an OEM key. OEM keys are typically locked to the original hardware (for example, a laptop motherboard) and may not be transferable. If your key is truly a retail license, the phone activation method should usually work.

    *Note: Don’t worry! Windows 10 and Windows 11 are practically identical except for the UI, the suggested steps should work for both systems.

    If these steps do not resolve the issue, let me know, and I’d be happy to explore rerouting your question for further assistance. I hope this helps, and please let me know if you have any additional questions! :)

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  4. Anonymous
    2025-01-27T00:17:10+00:00

    Hello there Francisco,

    I tried the method you suggested but unfortunately I get a message that says unable to activate Windows with an error code (0x80072ee7).

    I’m running Windows 10 contrary to the person in the method you suggested and I’ve followed the steps but to no avail.

    I’ve uploaded an image for reference.

    If you could help me out that would be great!

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  5. Francisco Montilla 30,635 Reputation points Independent Advisor
    2025-01-26T21:21:20+00:00

    Hi there,

    My name is Francisco. I'm an Independent Advisor and I'll be glad to help you today.

    There is a possible solution for your issue in a previous question, answered by the Independent Advisor DaveM121:

    https://answers.microsoft.com/en-us/windows/for...

    Please, let me know if this helps! :)

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