I am getting ready to move all the files on my internal Boot Drive to an Internal SSD Drive. So I have been trying to clean things up on my boot drive first. I have attached a ScreenShot. On the left the Get Info for that drive shows that I have 392 GB Used, but on the right if I list all the folders on that drive they only total about 336 GB. Any idea where the mystery 56 GB may be hiding???