KB article 982523 describes "Microsoft System Center Virtual Machine Manager 2008 R2 Admin Console issues resolved in the hotfix rollup package that was released on June 8, 2010."
"If a VM is configured to have 3 virtual processors, SCVMM Admin Console crashes. To resolve, install hotfix rollup package 982522 for SCVMM 2008 R2. And this hotfix rollup package also resolves issues documented in SCVMM 2008 R2 Admin Console update: 976246 When you remove a virtual hard disk from a virtual machine in SCVMM 2008 R2, .vhd file on Hyper-V server is deleted without without warning," explains Microsoft.
More Info: How to download and install roll update