In the Settings window, Go to the Protection tab. In the left part of the Settings window click on mail anti virus. In the right part of the Settings window check or unchecked the box Enable Mail Anti Virus. At the bottom of the window click on OK.
To update the database follow the instruction: In the desktop task bar notification area do right click on the application icon and then select update from shortcut menu. And next is in the main window, click database update and run update.