Error: 0xC004F050 The Software Licensing Service reported that the product key is invalid
Next, upgrade the existing key on the KMS host by running:
- "slmgr /upk" to uninstall existing key,
- "slmgr /ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx" to install new KMS key and;
- "slmgr /ato" to activate the new key.
- "slmgr /dlv" to verify the key has been successfully upgraded to support the new Windows 8. You should see "VOLUME_KMS_2012_C_channel" on the description.