Windows 2012 R2 Hyper-V event id's 20144 and 15130

Windows 2012 R2 Hyper-V.

After installing the May 2014 MS updates we can no longer start any of the guest VM's.  When attempting to start a VM the following is logged in the event logs:

Event id 20144 from Hyper-V-VMMS "Failed to start the virtual machine XYZ' because one of the Hyper-V components is not running"  and

Event id 15130 from Hyper-V-VMMS  "XYZ' failed to start"

We've looked at http://support.microsoft.com/kb/2761004/en-us  and as far as we see the I/O verification option in Driver Verifier is disabled.   We also uninstalled the May 2014 updates that we applied just before the problem started but this did not make a difference.

Help please.