Oh boy, here we go. Here's my setup: (10.6.3) Partition 1 - OS X (440GB) Partition 2 - Windows XP (60 GB) TOTAL: 500 GB Sunday night, almost a week ago, I had just about 40-80GB of free HD space. I'm putting in an interval because I was ripping some DVDs and some space was taken up. Fast forward to Monday morning: I wake my Mac from sleep and what do I see? How about "zero KB available" in Finder and a warning telling me my startup disk is full. I panic. I restart the computer, log back in, and I have 1GB of free space left according to Finder. Yep, 1 measly gigabyte. I shut off the Mac, get to class, and get back home. I reset my PRAM, NVRAM, launch in safe boot, create a new user to see if problem persists...and nothing, no dice, still displaying 1GB. Safe Boot doesn't fluctuate, tells me I have 1.5GB and it stays there. Only now, it's fluctuating. Goes from 1GB to 700, to 800, to 900, and back down to 700. Currently at 440MB. I run both OmniDiskSweeper and Disk Inventory X. BOTH tell me the same thing: that 360GB is in use on my HD. WHICH IS WHAT OS X SHOULD BE TELLING ME INSTEAD OF 700-1GB. I call AppleCare. I get transferred to a senior technician who tells me that this is the first time they hear of my problem, of my fluctuating/disappearing HD space. We talk for a couple of hours to no avail, she gives me a number and a case ID to reach her back. I keep trying, but she's always busy. Now I'm coming to you. Today, I launch Parallels, just a hunch...tells me I need to free up more HD space to run my BootCamp VM. I quit Parallels, and go check out Finder...I now have 133MB free, down from 440MB. 15 seconds later...I'm back at 440. I launch Activity Monitor, and a whopping 215GB of Virtual Memory is in use. I quit all programs and log back in. Same thing. What the hell should I do now? I can't backup with SuperDuper because the space is constantly fluctuating and it's always re-evaluating my files as a result. I now have no backup and my most important files (class notes/papers) stored on Dropbox. Is there an issue with my system's VM? Is my HD dying? Should I bail ship and take this to a Genius? Please please help.. EDIT: now I'm down to 400, and back to 408. I HAVE NOTHING THAT IS DOWNLOADING.