I have a bit of a tricky situation here: I bought a new MacBook (OSX 10.8) and want to use the same external HD for Time Machine as I was using with my old computer. The HD is 160 GB but it's full of old backups. The total size of my old MacBook's internal HD was only 50 GB, however. I would like to keep the latest backup of my old computer, just in case I need a file out of it at some point in the future. So theoretically, it should be possible to free up around 110 GB of free space on the external HD so I can use it for backups of my new computer. I know that the easiest way to do this would be to go into Time Machine with my old computer and manually delete all but the latest backup. But since I already sold that computer, this is not possible. Also, I've read about using the "tmutil" command in Terminal to manually delete backups. This doesn't work either. Can I only use the "tmutil delete" command on the same computer the backups of which I want to delete? Is there another solution for my specific case?