The Unofficial Apple Weblog (TUAW)

I don't know much about real-world forensics, except for what I see on television, but one thing I do know is that when you're faced with a troubleshooting mystery, you have a couple of choices: shrug your shoulders and fix the problem, or figure out what went wrong in the first place to try and prevent it from coming back again. While I don't always have the time or the smarts to suss out the root cause of every Mac issue, sometimes the issue is so curious and the cause so interesting that I feel compelled to investigate until I get to the bottom of it.

Recently, when one of my colleagues came in with a slightly-full hard drive, I went to my go-to disk space checker (the capable OmniDiskSweeper) to see where we could save a gigabyte or two. In addition to the usual suspects of iTunes podcasts long gone stale and legacy backups of Entourage databases, I came across the file you see above; it lives in ~/Library/Application Support/Chess. Why on earth would a support file for Chess.app be 1.5 gigabytes? That's crazy talk. I would love to delete it, but a file that large... might be useful or important.

Where did this bulky bucket of bits come from? Read on for the answer.