Windows 2012R2 VM Guests hang showing state Stopping-critical

Hi

I have a Windows 2012 R2 Std Server running Hyper V. I have 2 VM guests running windows 2012 Std R2. Since last week Windows backup on the Host was failing and the VM Guest was hanging. As of yesterday the VM guests Hangs intermittently or always on reboot. The VM Manager shows the guest state as "Stopping- Critical" and the only way to bring the VN Guest back up is to reboot the current Host server.

We have reinstalled Hyper-V on the host and it still does the same. The Host has been updated using windows update, still the same.

Dheren Maharaj