KB975426 - Virtual machines cannot migrate from a Windows Server 2008 stand-alone server to a Windows Server 2008 cluster after you upgrade to System Center Virtual Machine Manager 2008 R2. This one discusses an issue where SAN migration may fail with error 1600 after upgrading to to System Center Virtual Machine Manager 2008 R2: “You install Microsoft System Center Virtual Machine Manager (VMM) 2008 in a Windows Server 2008 cluster and on a stand-alone Windows Server 2008 server. You upgrade all servers to System Center Virtual Machine Manager 2008 R2 without uninstalling the old agents from the servers. You try to move a virtual machine from the stand-alone server to a clustered server by running a Storage Area Network (SAN) migration.” To work around, uninstall the Virtual Machine Manager 2008 agent from the servers, and then install the System Center Virtual Machine Manager 2008 R2 agents, KB975426.