http://blogs.msdn.com/virtual_pc_guy/archive/2004/12/23/331100.aspxEvery now and then someone will report that they are having problems launching more than 10 or so virtual machines under Virtual Server. Inevitably it turns out that they have enabled the /3GB boot option ( http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ddtools/hh/ddtools/BootIni_de16d3ec-c437-4628-805f-8945ea598a92.xml.aspen-USCommunityServer 2.1 SP1 (Build: 61025.2)