A Win guest, sitting quietly doing nothing, suddenly started eating 100% CPU. The display is messed up, showing buffered content but not redrawing what shows up when scrolling the Workstation screen. I told it to shut down the guest, and a while later it is still stuck. If I try to Quit the program it says "... cannot be closed while the virtual machine is busy." In the Workstation window, the VM Power options are greyed out so I can't force-reboot the guest either.
This is Workstation 11 on a Linux Mint host OS.