http://blogs.technet.com/cliveeastwood/archive/2007/05/29/mom-2005-windows-server-base-os-mp-05-0-3500-0010-supporting-windows-server-2003-r2-has-been-re-released-to-the-web.aspxFor those with a long memory, you may recall the Server Base OS MP 05.0.3500.0000 was withdrawn last October a short time after its release, due to technical issues. The most prevelent issue was that MOM agents could fail to restart on boot. See my earlieren-USCommunityServer 2.1 SP1 (Build: 61025.2)