When microsoft essentials security updating Manually definition update file runs, a file extraction dialog box appears. Please note that Microsoft Security Essentials can only be installed on Windows Vista and Windows 7, as on more recent Windows iterations it is superseded by Windows Defender. Save or run the file. System requirements. Therefore, no definition updates will be available in the future microsoft essentials security updating Manually Forefront Client Security. If your computer is running Windows Vista or Windows 7, click Start, click Documents, and then locate the folder where you saved the definition file. Next, restart your PC. If you don't already have Windows Defender Antivirus or other Microsoft antimalware or you want to reinstall it, see our threat protection catalog. Check whether your version of Windows is bit or bit. Browse to the folder where you saved the file, and then double-click Mpam-fe.