Windows Activation Error
0xC004C008: Key usage limit exceeded
0xC004C008 tells you the product key has already been used on the allowed number of devices. It appears when a single-device key is activated on a second computer, or when the same key was previously entered on another installation. If the key will live on only one device, phone activation usually resolves it; otherwise contact your seller.
Most common causes
- A single-device key was entered on a second computer
- The same key was used on another installation in the past
- The key was sold to multiple people (untrustworthy source risk)
Step-by-step fix
- Make sure the key is used on a single computer; if the old device is retired, continue.
- Press Windows + R → "slui 4" for phone activation; if the key can move to a single device, the wizard issues a confirmation ID.
- Run Settings → System → Activation → "Troubleshoot".
- If the error persists, contact your seller and ask them to check the key's usage history; invoiced purchases qualify for replacement.
Frequently Asked Questions
Can I use the same key on two computers?
Individual Windows keys are for a single device. Two computers require two licenses; anything else produces this error and activation revocations.
I replaced my computer and my old key throws this error. What now?
The phone activation wizard is designed for this scenario: if the old device is out of use, try confirming the key on the new installation through the wizard. If that fails, clarify your license type's transfer terms with your seller.
Still not resolved?
If you bought your key from Karınca Lisans, send the error code to our WhatsApp support line — we will solve it together. If the problem is an old or mismatched key, our Windows 11 Pro key page offers invoiced licenses with the type clearly stated, delivered within minutes. For setup steps, see our instructions library.