Activation Failed [Error Code: 0xC004C003] HWID 3.12

[Alshami8]

This error was not fixed in 3.12, and TSforge doesn't work for me

[tted3286]

NTLite should not let you install a service pack past October 2025 for Win 10 IoT Enterprise LTSC 2021.
This means the activation method should still work unless you installed a smaller update that is poison.

<File>C:\Users\Awesome\Documents\Updates\SSU-19041.7183-x64.cab</File>
		<File>C:\Users\Awesome\Documents\Updates\windows10.0-kb5087593-x64_1dc5580af8ac09eba78fd21e1c21148e085b8899_05.cab</File>
		<File>C:\Users\Awesome\Documents\Updates\Windows10.0-KB5066791-x64.cab</File>

One of those updates is .net, the one is the october 2025 (biggie) and the SSU is from May or June (biggie). You can also safely add the safe OS update to update the bootloader. Include no other Windows update other than Appx stuff.

With the internet off, change the product key to the following.
QPM6N-7J2WJ-P88HH-P3YRH-YY74H
Restart your computer.

Download this and put the loose files in C:\Files

GOTO C:\Files
Click on the file gatherosstatemodified.exe, go to properties and set the compatibility mode to Windows XP SP3.

Run Powershell as Administrator, Copy the contents BETWEEN the brackets paste and enter into powershell:

[$value = (Get-ItemProperty HKLM:\SYSTEM\CurrentControlSet\Control\ProductOptions).OSProductPfn

C:\Files\gatherosstatemodified.exe /c Pfn=$value`;PKeyIID=465145217131314304264339481117862266242033457260311819664735280]

Both original and modified gatherosstate must be in Files Folder.
The internet must be ON.
Otherwise, it won't work.

clipup -v -o -altto C:\Files\

slmgr /ato

slmgr /xpr

Both original and modified gatherosstate must be in Files Folder.
The internet must be ON.
Otherwise, it won't work.

Again there is no way for Microsoft to patch this exploit in a manner that is deployed in NTLite since they patched after October 2025, and you can only apply the October 2025 patch. I've activated the same edition recently, so unless they just started block the key, you know "out of the blue", "mid-summer" it should work. But tell you it worked days ago, so it will be quite the slap in the face if it doesn't work for you now.

And Windows 11, particularly 23H2, I am getting the same error (however I did integrate the latest service pack meaning I provided poison). If you look at the mass 3.12 changelog, the changed the HWID Installation ID to:
221306452340115677963964261259250411589493550039199940431586886

So if the above doesn't work, re-try with that installation ID; this meant remove "the block" if Microsoft put one.
You thought it was tied to the key, but it could simply be tied to the installation ID.

[ave9858]

This error was not fixed in 3.12, and TSforge doesn't work for me

what's the output of fix licensing?