Every day brings new malicious software. So every day, our team sends updates to Microsoft Security Essentials to help keep you protected.
To block the latest bad programs, Microsoft Security Essentials relies on virus and spyware definitions. Follow these steps to make sure these definitions stay up-to-date.
Click Settings, and then click Scheduled scan.
Make sure the Check for the latest virus and spyware definitions before running a scheduled scan check box is selected, and then click Save changes. If you're prompted for an administrator password or confirmation, type the password or confirm the action.