So I managed to interrupt the computer when I selected the "Erase Free Space" option. I had 0GB left on the computer and had to cancel almost all of the applications. I Googled and found that /var/root/Library/Caches/TemporaryItems should locate the file when entered in Terminal, but whenever I try that, it just says "Permission denied." It only asked for a password once, and when I tried entering it, it said that there was no such file. I located a few other temporary files and deleted those, and also tried making empty folders on the desktop to empty the trash. It freed up 6.7 GB, but there's still a lot of space missing. I'm not sure what else to try or how to get the space back. Please help! Thank you.