Posted by (JavaScript must be enabled to view this email address) on Tue 17 Nov 2009

On resetting a dev machine on Hyper-V after setting up a Windows 2008 machine we found that we could no longer connect to a virtual machine.

The Hyper-V console told us that “The authentication certificate has expired or is invalid” - I found this helpful forum entry.  The issue is that the self issued certificate had expired.  To re-create a new certificate I deleted the old certificate and then restarted the Hyper-V Management service to regenerate the certificate.