Activation error

0xC004C008

The activation server determined that the specified product key could not be used

The product key has exceeded its activation limit on Microsoft's servers. Each key type has a fixed number of activations; once they are consumed (including by reinstalls), the server refuses further use. Volume (KMS host) keys are capped at 10 activations across no more than six computers.

Symptoms

Error text: "The activation server determined that the specified product key could not be used"
slmgr.vbs /ato fails although the same key worked previously
slmgr.vbs /dlv shows License Status "Notification" with Notification Reason 0xC004C008

Causes

The key's activation count is exhausted — extra reinstalls consume activations on some key types
A KMS host key (CSVLK) passed its limit of 10 activations on 6 computers
A MAK consumed all of its purchased activation count

How to fix it

Inspect the current license state

Run slmgr.vbs /dlv in an elevated Command Prompt. The "Product Key Channel" line shows the key type (Retail, OEM, Volume:CSVLK, Volume:MAK) and the license status explains the server's refusal.

Use phone activation for retail keys

Press Windows + R, run slui 4, pick your region, and call the number shown. Provide the Installation ID and enter the Confirmation ID you receive — phone activation is the documented path for retail keys close to their limit.

For MAK/CSVLK keys, contact the licensing activation center

Volume keys that exceeded their activation count need Microsoft's volume licensing support to add activations or reissue the key. This cannot be fixed client-side.

Install a different key

If you have another valid key for the same edition, run slmgr.vbs /ipk <newkey> and then slmgr.vbs /ato to replace the exhausted one.

Still need help?

If error 0xC004C008 keeps blocking activation after these steps, our support team can check your key and license channel directly.

Contact support

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