Virtual box gets hanged after removing usb of wireless keyboard/mouse.
Your problem may be due to a deficiency of Virtualbox 4.3.16. Revert to 4.3.14 to resolve the issue. If this does not work, ensure the proper support is there for USB hardware or the specific device you are using. Also, check the “/etc/fstab” file for the right information. You also may have to manually remove/unmount the device in Virtualbox to avoid this problem.