I woke up today with my MacBook Pro's (internal, boot) hard drive completely full. It should have about 100 GB free (out of 500). So I searched around and tried some of the common solutions: removing the sleep image; trying Omni Disk Sweeper and DaisyDisk; emptying the trash; rebooting a couple of times. They didn't help. The really strange thing is that Omni Disk Sweeper and DaisyDisk don't see the extra space: once Omni Disk Sweeper sizes my disk, for instance, it sees a total of 388.8 GB of data, while "get info" on my hard drive says I have 497.2 GB used. But if I look at the four folders at my root level (Applications, Users, System, and Library), their reported sizes add up to 409 GB, not 497 GB. The triggering event was likely an effort to update a SuperDuper! backup overnight: it failed after about an hour. I see entries in my Console logs for SuperDuper! and a few background processes running into trouble because of a lack of disk space, but I don't see any entry that screams "I will now create an 80-gig log file." And if there is such a file, I can't find it. I'm running 10.6.6 and SuperDuper! 2.6.2 (v87), which is the latest version, on a recent MacBook Pro. Any ideas?