Because malicious software is continually being developed, Forefront Endpoint Protection relies on up-to-date definitions to determine if software that is trying to install, run, or change settings on your computer is potentially unwanted or malicious. Forefront Endpoint Protection updates the virus and spyware definitions on your computer automatically. If the definitions haven’t been updated for over seven days (for example, if you didn’t turn on your computer for a week), Forefront Endpoint Protection will notify you that the definitions are out of date.