Error Database · Windows

0xC004C008

Quick overview: 0xC004C008

This error means the product key has already been activated on the maximum number of devices Microsoft allows for that license type. Retail keys typically allow transfer between machines, but each transfer consumes an activation slot until the old installation is deactivated.

This page documents Activation Limit Reached on Windows. Activation codes are licensing checkpoints—they rarely indicate hardware failure. Use the steps below before assuming your product key is permanently invalid.

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Activation Limit Reached

Error code: 0xC004C008 Platform: Windows Updated: 2026-07-17

What This Error Means

This error means the product key has already been activated on the maximum number of devices Microsoft allows for that license type. Retail keys typically allow transfer between machines, but each transfer consumes an activation slot until the old installation is deactivated.

OEM keys are bound to the first motherboard they activate on and cannot be moved to a new PC. If you replaced major hardware or are reusing a key from an old machine, you may hit this limit even with a legitimate key.

How to Fix It

  1. On your old PC, open an elevated Command Prompt and run: slmgr /upk then slmgr /cpky (retail keys only).
  2. Restart both machines and try activation again on the new device.
  3. If you changed motherboard or hard drive, use the automated phone activation wizard (slui.exe 4).
  4. Sign in to your Microsoft account on the activated device — digital licenses may re-link automatically.
  5. If the key is OEM and you built a new PC, you will need a new license rather than reusing the old key.