Activation error 0xC004C003: causes and fixes

This code means the activation server refused the key, or found no licence for this PC.

Possible causes

• The key was typed wrongly.
• The key is blocked by Microsoft.
• You upgraded to a Windows edition this PC has no licence for.

How to fix it

1. Retype the key carefully. Mixed-up 8 and B are common.
2. Check the installed edition against the key.
3. Wait an hour and retry if servers are busy.
4. Try phone activation.

What not to do

Do not try keys from lists online: see why free Windows keys do not work.

Bought from us? Send the screenshot and we replace the key.