For some reason, Thunderbird freaked out on me and when I sent a JPG to a coworker, it was corrupt. Normally this wouldn’t be a problem. However, due to Finder and Preview integration it was.
The symptom was that after viewing the corrupt JPG, Finder kept crashing and restarting repeatedly. We went through the standard step of booting into a console and then deleting the Finder .plist files and rebooting. That didn’t fix the problem.
After thinking about it for a bit, I surmised that what was likely happening was that Preview was FUBARed due to the corrupt file. Preview was trying to run when Finder opened and was crashing and causing Finder to crash. Of course, Finder is designed to restart automatically when it crashes so it was very annoying to try to work without Finder and with it flashing in and out every couple seconds.
So, we had just booted into safe mode so we deleted the corrupt JPG and the Preview .plist file. After a reboot, everything was peachy.
One question that I couldn’t find an answer to is how to run an application (e.g. Console) when you can’t open Finder and don’t have it on your dock, without having to boot into console or safe mode?