One day, I got bored and read Chimera Release Note. Under "Known Issues", I found:
Sometimes, on Mac OS 10.2 (Jaguar), Navigator won't stick as your default browser. If you have this problem, try removing the following filesIt may take one or two tries to get it working, but this really works! Close all running applications, flush the cache files, change the default web browser, flush the cache again (if they exist), and reboot.and reboot your machine.
- ~/Library/Caches/com.apple.LaunchServices.UserCache.csstore (where ~ is your Home directory)
- /Library/Caches/com.apple.LaunchServices.LocalCache.csstore
[Editor's note: I realize this makes five hints on this subject now. Each approach has been very independent of the others, and the question is obviously of interest to many people, so I've felt that each merited its own hint. Hopefully 10.2.1 will make all five of these hints meaningless!]

