When you log out of MET/TEAM, your user license is released and all resources are cleaned up. You are prompted to close the browser. Selecting Yes causes the browser to try and close the browser tab. Based on your browser security settings, this will not always work. In the case that your browser prevents this action, the tab is left in a clean state and may be manually closed. Selecting No, leaves the browser in a clean state ready to be manually closed.