Literally two hours ago I had about 150 GB of empty space in my startup disk, now I have (apparently) 9.2 MB. The only things I've done are watch Netflix, browse Facebook, and get Terminal to erase free space. Terminal has finished now, and come up with the error message attached. Any solutions? --- Post Merged, Apr 5, 2016 --- UPDATE: Immediately after quitting Terminal I gained back the 138 GB that was full. This was confirmed by both Disk Utility and About This Mac. Anyone know WHY this happened in the first place?