As someone recently asked me how to  unmount an external disk: a) by forcing it to unmount: sudo unmount <harddisk> e.g. sudo unmount /Volumes/hdd_xyz ...which is really dangerous because you force your disk controller to throw out your drive even it is working for you... (risk of dataloss):/ b) [Better solution] find your real enemy: sudo lsof | grep /Volumes/xyz and try to stop, eliminate those working, open files from your disk drive <xyz>

Having trouble to shutdown your VirtualBox since you upgraded to OS X 9 (Mavericks)? [Solved] Write a short bash script, to remove your virtual vboxnet(XYZ) network adapter, which causes this failure! #!/bin/bash VBoxManage hostonlyif remove vboxnet<xyz> VBoxManage hostonlyif create Remember to make it executable: chmod +X <scriptname_xyz> So all we do here is to remove our vboxnet<xyz> "host only" network adapter by executing this script after we tried to shutdown our virtual box machine! The script successfully recreates the adapter with the "saved" settings... (<xyz> = 0...n in most cases write vboxnet0)