Rob was using Adobe Premiere to edit his video, but he ran into problems when his external hard drive gets unplugged. Leo says that if a hard drive suddenly gets disconnected, OS X doesn't like it. Modern operating systems use a journaling setup that will save up a bunch of data before it writes to the hard drive. That's why OS X wants him to eject the drive first before disconnecting. When he disconnects while the hard drive is writing, then the hard drive writes a kind of 'word salad' to the hard drive that could corrupt it. He'll need some recovery software that can fix the file table. And he'll lose some of it even if he does recover it.