Hyper-V Error "cannot connect to the virtual machine because the authentication certificate is expired"
This error appeared on one of my Hyper-V servers this morning. A search of TechNet revealed that KB967902 has an update that can be downloaded to correct the issue. The issue occurs because the because the Hyper-V Virtual Machine Management service (VMMS) certificate has expired. There is a blog entry here that explains how to correct the issue by renewing the certificate manually.