If your running System Center Virtual Machine Manager (SCVMM) you should take a look at KB 962941.  The KB describes and links to all of the recommended Windows hotfixes, SCVMM hotfixes and Hyper-V server hotfixes that are important for SCVMM functionality.

KB Article Link:  http://support.microsoft.com/kb/962941


Taylor Brown
Hyper-V Integration Test Lead