Ben Armstrong has a little blurb about a fix included in the latest rollup for Windows Server 2012 R2
http://blogs.msdn.com/b/virtual_pc_guy/archive/2014/01/08/virtual-machines-not-shutting-down-on-host-shutdown-in-windows-server-2012-r2.aspx
http://support.microsoft.com/kb/2896800/en-us
Hyper-V guest OS does not shut down when you restart the host computer that is running Windows Server 2012 R2 or Windows 8.1
Consider the following scenario:
- You set up a Hyper-V virtual machine on a host computer that is running Windows Server 2012 R2 or Windows 8.1.
- You set the Automatic Stop Action setting of the virtual machine to Shut down the guest operating system.
- You restart the host computer.
In this scenario, the guest operating system (OS) on the virtual machine does not shut down. Additionally, after you restart the virtual machine, the following event is logged on the guest OS:Event ID: 6008
Message: The previous system shutdown at time on date was unexpected.
Note If the computer is part of a cluster, this issue does not occur.
This issue occurs because the Virtual Machine Management Service tries to shut down the virtual machine by using the Virtual Machine Worker process. However, the process encounters a logic failure that causes the shutdown operation to fail and reverts the shutdown operation. Therefore, power cycling occurs instead of a clean shutdown.
Update information
To resolve this issue, install update rollup 2887595. For more information about how to obtain this update rollup package, click the following article number to go to the article in the Microsoft Knowledge Base:
2887595
Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 update rollup: November 2013