After today’s heat about Morro / Microsoft Security Essentials (here and here), Microsoft is releasing an update to Forefront Client Security v1:
Improvements to the FCS kernel-mode driver
A change in how the component object model (COM) is used in Software Explorers. There is an issue present, only in Windows 2000, that causes it to crash.
A change to how the FCS engine scans shortcut files(.lnk). The engine can now be configured to query the path to which the shortcut points; if the path is on the local computer it will scan the referenced location, if it is a network location it will not scan the reference
Source: WSUS Product Team Blog