Extract with WinRAR using the password above, then run as administrator. Works on Windows 10, 11, Server & Office.
⚠0xc004c003
Product Key Blocked
The product key has been blocked by Microsoft activation servers. This typically affects retail keys used on too many machines.
1
Switch to KMS activation
KMS uses volume licensing keys (GVLKs) which are never blocked. Run KMSPico to switch your activation method entirely.
2
Install the correct GVLK
In elevated CMD: slmgr /ipk W269N-WFGWX-YVC9B-4J6C9-T83GX (adjust per edition — see GVLK list).
3
Activate via KMS
Run slmgr /skms kms.windowskms.com then slmgr /ato.
4
Verify
Run slmgr /xpr to confirm the switch to KMS activation.
Reset License with slmgr
Run these commands in an elevated Command Prompt (right-click → Run as administrator):
> slmgr /rearm
> slmgr /ato
> slmgr /xpr
What error 0xC004C003 means
0xC004C003 means the activation server reported the product key as blocked. The key you (or Windows) tried to use has been flagged on Microsoft's side — usually because it's a leaked retail key that's been entered on thousands of machines, or a key that was cancelled. It is a key problem, not a fault with your PC or your Windows files.
Why it happens
A widely-shared "free" retail key found online has been blacklisted.
A key was used past its allowed activation count.
An OEM key from a different device was entered manually.
The clean fix
Because the issue is the key itself, the fix is to stop relying on that blocked key and activate through KMS instead. KMSPico installs a local KMS host and applies the correct Generic Volume Licence Key for your edition automatically, so there's no blocked retail key in the picture at all. Prefer to do it by hand? Remove the bad key with slmgr /upk, then follow the slmgr activation commands.
Product Key Blocked. It indicates the product key has been blocked by microsoft activation servers. this typically affects retail keys used on too many machines. Follow the steps above to resolve it.
Yes. In most cases this error is fixable without reinstalling Windows by running the appropriate slmgr commands or downloading a fresh KMS activation package.
Yes. KMSPico resets the license state and applies a fresh KMS activation, which resolves most Windows activation errors including this one.