So for all of us that've been struggling with VPC 2004 on a Vista host - Windows Virtual PC 2007 Beta 1 has been released on Connect. There are 32-bit and 64-bit flavors (yes 64-bit hosts are supported now). Not sure when it'll be available on MSDN - not there yet. If you're a Vista user and developer/infrastructure type this is your chance to get involved and help flesh out the product. VPC 2007 Beta 1 adds support for Windows Vista as a host and quest operating system (Business, Enterprise, and Ultimate Editions only).