Fix Activation Error code 0xC004C003 Product key blocked

So you Took advantage of Free Upgrade to Windows 10 for Windows 8.1 and 7 users ? Well done, With All new Windows 10, Also comes Errors and bugs which Microsoft will be working hard to fix but One of the Common error that most of the New Windows 10 users are getting is Error code 0xC004C003. Its a Activation error which says the server determined the keys to be invalid or keys are blocked.

For users who Directly Upgrade to windows 10 from Windows 7 or 8.1, There should not be such error. But this activation error will be shown to those who Fresh installed Windows 10. I will try to help you Fix this Activation Error 0xC004C003 in Windows 10.

Reasons of Error code 0xC004C003

There is no Surprise that Windows Servers are over loaded and this might be the reason you are seeing this error. The solution to this is to play waiting game and one fine day you will automatically see that you windows is activated. So if you have upgraded to windows 10 and have not done clean install than this might be the reason.

You are Seeing this 0xC004C003 Error Because you have Fresh Installed Windows 10. Which resulted in Deleting Everything that your previous version had including the Product key. Now lets see how to fix this Issue.

Fixing Error code 0xC004C003

Error code 0xC004C003

If you have Fresh Installed Windows 10, Meaning Not Upgrading to windows 10 from your Windows 8.1 or 7 then you might not be able to Revert back to your Previous Windows from Win10.

Method 1: Reset your PC.

Resetting your PC might just Help you to Solve this issue.This doesn't Work always but its worth the try. Follow the below mentioned steps.

Step 1: Click on Start button, then go to Settings

Step 2: Click on Update and Security.

Step 3: Now on the left Pane you will goto Recovery.

Step 4: You will see Reset this PC Option so Click on Get Started.

Step 5: Sit Back and wait until everything is over and see if the Error 0xC004C003 is Fixed.

Note: Please Understand that you will loose all the files/Folders from the drive where Windows 10 is installed. Make sure you take a backup for any of your important Files before you Perform above steps to Fix code 0xC004C003 Product key blocked in Windows 10

Method 2: Installing Windows 7/8 then Upgrade.

There is not many things that you can do in this situation but you can always install Windows 8.1 or Windows 7 again and use the Free Upgrade Feature to get rid of Error 0xC004C003 Product key blocked.

Once you have upgraded to windows 10, Now you can try to do a clean install without errors. follow the below steps.

Step 1: Insert your Windows Installation CD/DVD of which you have a Product Key.

Step 2: Boot your PC through DVD by Changing Boot Priority in BIOS.

Step 3: Go Through All the steps that are required to Fresh installed Windows 7 or 8/8.1.

Step 4: Make sure whatever versio of Windows you just installed is activated, Now If you Wish to Upgrade to Windows 10, Download all the available Updates so that you can see Windows 10 Notification in the tray.

Step 5: If you can't see the Notification then you might want to Download Windows Media Creation Tool from Microsoft. 
Step 6: Now Run the tool and Use Upgrade this PC option so that it will download Windows 10 and then ask you few things before installing without any issues.

Step 7: Once the Installation completes you must now have Windows 10 and your copy should be Activated without any activation error like 0xC004C003.

Now if you wish, you can do a clean install of windows 10 through USB flash drive. Skip if asked for Keys while Clean installing Windows 10 This time. Don't Enter your Windows 7/8/8.1 Keys.

Most of the time we Provide Multiple Ways to solve errors but currently we know only Two way to solve this Error code 0xC004C003 Activation issue. We will update this post as soon as we find more ways to get rid of it.

Feel Free to let us know if you have any other ways to solve this error particularly in Windows 10.


Please don't tell anyone to reset their windows 10, the internet is full of horror stories of time taken for resetting, right from 4 hrs to 16 hrs, still doing !


Hi Shrinivasan. As this activation error is shown on Windows 10 and Logically after upgrading to windows 10 there won't me any thing important in the Windows Installation Drive for Users. It would be safe to Reset the PC and see if that solves the issue..

Do you mean its taking 4hrs to 16hrs for you to reset your PC? Thats bizzare.

I have mentioned 2 methods. Victims of this error can also start all over again.

Thanks for your Comment.


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