TeamViewer shows details about active sessions, including logs of connections and partner identifiers. You can check the "Connection History" in the settings to find any sessions that you did not start. Surprising pop-ups or requests to share your screen serve as further signs. Reviewing these logs and updating your TeamViewer password frequently is essential to prevent any unauthorized access. Activating two-factor authentication provides additional security and notifies you if an unrecognized device tries to connect.