I have a Windows 2008 R2 server that is a Hyper-V host (Dell PowerEdge T300). Today for the first time I encountered an odd situation; i lost connection with one of the guest machines but logging on physically it seems the guest OS is still running but no longer contactable via the network.

I tried to shut down the guest machine (Windows XP) but it would not shut down, getting stuck in a "Not responding" dialog box that cannot be dismissed. I used the Hyper-V management console to reset the machine and it could not get out of resetting state.

I tried to save another Windows 2003 guest machine, and it would be progress with its Saving state (0%). The other running Windows 2003 guest was stuck in the logon dialog.

My first suspicion is perhaps one of the Windows update patches this week (10 Nov 2011) may something to do with it, which was still pending a system restart. Well, since I could not do anything with Hyper-V i proceeded with the Windows Update restart, and now it is stuck half an hour at

"Shutting down hyper-v virtual machine management service"

Prior to restarting I did not observe any hard disk errors reported in the system event log; doubt it is a disk-related condition.

Shall I force a hard reboot?

UPDATE

As per answer report, it eventually restarted itself.