I have an external Fujitsu-Siemens, 1Tb, and I made 4 partitions: 1 for the Lenovo Desktop (with Windows8), 1 for the Shuttle Desktop (with Ubuntu Linux), 1 for the MacBook (with Yosemite, as Time Machine) and 1 spare partition. I use the Fujitsu for back ups. No problem at all with the Lenovo and the Shuttle but in the MacBook doesn't show at all, not even in "System" or "Start up disc". Please, help. Thank you.