These experiences highlight a pattern:
Windows 10 Pro can be activated via a corporate KMS server. KJ Activator likely creates a fake KMS server on your local machine (or redirects activation requests to a remote server). Your Windows system believes it is talking to a legitimate Microsoft Volume Activation server when it is not. This grants a 180-day activation, and the activator typically installs a scheduled task to re-activate every 180 days automatically. kj activator windows 10 pro 64 bit