Fix: Windows Activation error 0xC004C003

Error 0xC004C003 is a windows activation error which usually comes up when you try and activate your windows 10 after a clean install. Windows 10 is offered as a free upgrade if you are upgrading from a previous installation of Windows 7/8 or 8.1. Users who have upgraded from a previous install; have least faced the activation issue but there is a tricky part here you need to understand.

Since Windows 10 is offered as a free upgrade; there is a mechanism in place for activation, which is that it carries the information required to activate during the upgrade to easily activate Windows 10.

Now if you are doing a clean install without upgrading; it won’t carry the information from your Windows 7/8/8.1 install so you will need to buy a key because Windows 10 thinks that it is a new install.

But with these methods below and a clear understanding; you do not need to buy a key.

Activating a clean install of Windows 10

Directly installing Windows 10 by creating a boot able media without first upgrading from a previous install causes issues. If you have done this; then you will need to go back to your older / previous install (windows 7 / 8 / 8.1); activate it using the keys you have (this is usually located on the bottom  or back on the Certificate of Authority) then run windows updates and re-do the upgrade.

After the upgrade; Windows 10 will activate instantly and automatically. Once that’s done; run the following script by saving it as a vbs file.

Set WshShell = CreateObject("WScript.Shell")
MsgBox ConvertToKey(WshShell.RegRead("HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\DigitalProductId"))

Function ConvertToKey(Key)
Const KeyOffset = 52
i = 28
Cur = 0
x = 14
Cur = Cur * 256
Cur = Key(x + KeyOffset) + Cur
Key(x + KeyOffset) = (Cur \ 24) And 255
Cur = Cur Mod 24
x = x -1
Loop While x >= 0
i = i -1
KeyOutput = Mid(Chars, Cur + 1, 1) & KeyOutput
If (((29 - i) Mod 6) = 0) And (i <> -1) Then
i = i -1
KeyOutput = "-" & KeyOutput
End If
Loop While i >= 0
ConvertToKey = KeyOutput
End Function

Save the key to a safe place. It is better to save it; even though you may not need it again.

Now that it’s upgraded; and activated head over to the link below; follow the steps and do a clean install from the media creation iso:

Note that now you’re doing a clean install; after upgrading to Windows 10.

You have now also saved the key; which you can use if needed.

To summarize this; read the note below.

If you upgraded to Windows 10 on this PC by taking advantage of the free upgrade offer and successfully activated Windows 10 on this PC in the past, you won’t have a Windows 10 product key, and you can skip the product key page by selecting the Skip button. Your PC will activate online automatically so long as the same edition of Windows 10 was successfully activated on this PC by using the free Windows 10 upgrade offer.

There are many other methods and work arounds; however i find the one i posted easy and clean. Most users fails to understand how it all functions; technically when you do the upgrade (as a free upgrade) from a previous install; windows 10 is tied to your hardware and it uses this information to activate it self.

Kevin Arrows
Kevin is a dynamic and self-motivated information technology professional, with a Thorough knowledge of all facets pertaining to network infrastructure design, implementation and administration. Superior record of delivering simultaneous large-scale mission critical projects on time and under budget.

Expert Tip

Fix: Windows Activation error 0xC004C003

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