KMS (Key Management Service) is a legitimate technology developed by Microsoft for volume licensing in corporate or educational environments. It allows organizations to activate multiple devices through a central local server instead of individual product keys. Third-party "activators" like attempt to mimic this process:

The use of KMSMicro for activating Microsoft products without a legitimate license is against Microsoft's terms of service. Microsoft allows activation through KMS for organizations with a valid license, making KMSMicro's use in a non-organizational context potentially unlawful.