Issue/bug with Virtualbox & Windows Server 2012 R2

[Jack69]

Hey, I believe this is bug, but correct me if I'm wrong.
My host machine is Windows 7 Enterprise x64, with latest updates.
I use latest version of VirtualBox 4.3.12.
I have installed Windows Server 2012 R2.

However, if I try restart server, it goes stuck in "Restarting".
Is there any workaround, how I can fix this behavior?

Otherwise, I cannot use virtualbox and latest Windows Server. =/

[noteirak]

Minimum information needed for assistance.