I'm on a mac 10.6.8 with 2GB RAM, capacity of startup disk is 159.7 GB. Every week or so, mysteriously over night, the startup disk will go from having around 60GB of free space to 0GB. I regularly delete all downloads/documents, empty my trash, and empty my browser history. Not using an external drive. I've disabled the mail app, time machine is turned off, and I have run repair disk permissions in disk utility and rebooted a number of times. I also downloaded and tried omnisweeper but still couldn't find the source of the mysterious files/folders taking up so much space. When I go through every folder on the drive and compare it to another computer with an identical image, I get the same sizes, so I can't figure out what is taking up the space. HELP ME!