Hi. I have a 1 TB hard drive inside of my 2008 Mac Pro. Almost all of it is free; however, I just tried to download a software and do a Mavericks update, and I'm getting the same message that states I don't have enough hard disk space. Any thoughts on what this can be? I double-clicked on that HD and clicked "Get Info," and there's hardly anything used up. I did transfer a bunch of movie, music, documents, and pictures from my Time Capsule and previous Mac Mini, but according to this 1TB HD, I still have room to store much, much more, and it is nowhere close to full. There's also a 2nd 500GB hard drive, but that's not been used, but just to be sure, I double-checked, and it has more more (percentage-wise) than the 1TB. Thanks. Edit: Here is the exact message: Your startup disk is almost full. You need to make more space available on your startup disk by deleting files. I don't have anything called Macintosh HD on this Mac Pro, either. Thank you.