I've been noticing a weird trend with my rMBP, I always seem to have less space than I think I should. I don't check my free space that often, but when I do I'm surprised at how little I've got compared to the amount of stuff I store locally. Last night I checked and had 78GB free, this morning (after my rMBP had done nothing but sleep all night) I had 40GB. This was weird, so I checked the Storage tab in the About This Mac window and I currently have 142GB of space taken up by 'Other': Any ideas what this could be? And why it's inexplicably getting bigger? I'm guessing ~10GB is my ML install, but that still leaves 130GB being filled by phantom data.