Hello,

* If you meant Microsoft Forefront Client Security definition updates
You can download the latest definitions manually.

Please follow this link:
http://www.microsoft.com/security/portal/Definitions/HowToForefront.aspx#FSS32bit

To download the Microsoft Forefront Client Security antimalware definition update file(Mpam-fe.exe) for 32-bit (x86-based) versions of Windows, click the following link:
http://go.microsoft.com/fwlink/?LinkID=87342&clcid=0x409

To download the Microsoft Forefront Client Security antimalware definition update filefor 64-bit versions of Windows, click the following link:
http://go.microsoft.com/fwlink/?LinkID=87341&clcid=0x409

You have instructions for a 32-bit system and instructions for a 64-bit system update.

* If you meant the Microsoft Forefront Server Security engines Updates, Please follow this link:

http://support.microsoft.com/kb/950547/en-us

APPLIES TO

* Microsoft Forefront Security for Exchange Server
* Microsoft Forefront Security for SharePoint
* Microsoft Forefront Security for Office Communications Server

To download the .cab file of the latest scan engine update, visit the following Microsoft Web site:
http://forefrontdl.microsoft.com/server/scanengineupdate/x86/<EngineName>/Package/<PackageVersion>/EngineName_fullpkg.cab


Don't hesitate to ask us any question.