VirtualCenter virtual machine console goes black when the virtual machine is reverted to a snapshot through the GSX Server console (1483)
The virtual machine console goes black when that virtual machine is reverted to a snapshot. If you are in full screen mode when this happens, you might be stuck in full screen mode.
To get out of full screen mode, press Ctrl+Alt+Del or Alt+Tab. Then open the Windows task manager and end the vmware-remotemks.exe process.
Also, try refreshing the tab of VirtualCenter console by clicking a different tab, then clicking the Console tab again. This action returns the console to its normal state.