If you launch the Microsoft Security Essentials anti-virus database update file , a file extraction dialog box appears with the message that the virus definitions are being updated.
After the file extraction dialog box closes, you can check if the definitions of viruses and spyware have been updated. To do this, open Microsoft Security Essentials and click the Update button, and then check the status of virus definitions and spyware.
Note : To install the correct version of the virus definitions and spyware updates for Microsoft Security Essentials, you need to know the bit width of your XP, Vista or 7 system. In addition, you must log in with administrator privileges.
With the help of these databases, you can also update the Defender antivirus in OS 8 / 8.1 / 10.