Just earlier, SCVMM (great management tool for Hyper-V) reported that one of our Hyper-V cluster nodes stopped responding. We raised a ticket with Microsoft Technet. After some days of troubleshooting with the great Chinese Microsoft engineers (with my limited Chinese vocabulary), it was discovered that the Performance Monitor (Perfmon) WMI of the affected node was corrupted and hence unable to report to the SCVMM host.

To rebuild the perfmon WMI, enter the following command using elevated command prompt at the system32 prompt:
C:\Windows\system32 > lodctr /R
Re-sync the perfmon counter with WMI by running winmgmt /resyncperf.
C:\Windows\system32 > winmgmt /resyncperf
And then restart the WMI service. The parameter 'R' for lodctr must be in capital for the rebuild. This parameter is not even documented on
Microsoft Technet.