"So there are Oliphaunts. But no one at home will ever believe me."
Random header image... Refresh for more!

Corrupting your Preferences

There is nothing more insidious than having your preferences corrupted. Of course I’m talking about the file that stores your configuration information from an application running in Mac OS X becoming unreadable to the computer, causing unpredictable results.

Every application stores information about itself in something known as a property list file, or plist file for short. Any well-behaved application will create it for you if it is missing. This happens, for example, the first time you run the program. If this configuration file gets corrupted—for example, if there was a crash while it was being updated—then the program may not be able to read it the next time it starts up. Rather, it may be able to read it, but only partially, yielding strange, incomplete, or undefined options controlling the behavior of your application.

This happened to me recently when iChat refused to start up with the video camera enabled. It would tell me that the computer did not support video conferencing. However, it was able to turn the indicator light for the camera on, and all other programs using the camera worked fine. A bit of Google searching revealed that iChat is particularly susceptible to having its plist file corrupted in a way that has this effect.

Even if you don’t have a reason to suspect the preferences file, it is not a bad troubleshooting technique, when you are up against the wall and everything else has failed. So it’s a good technique to remember.

Most plists will live somewhere in your Home folder’s Library. In my case, I found the .plist for iChat in Home/Library/Preferences. It’s name was com.apple.ichat.plist. Quitting iChat, deleting the file, and restarting iChat solved the problem.