I am running Ubuntu 11.10 on Oracle Virtual Box 4.2.4 under Windows 7 x64.
To stop guest system I often use
halt command which works fine on physical machines. But it looks hanging on virtual ubunty. After
halt it starts shutting down, Ubuntu logo appears with dots below flashing. After some cycles it just stops. VM manager does not feel machine is gone, so I need to power off it.
The system stops Ok if I shutdown it via GUI.