I use Thunderbird for my mail client, and have my client set to automatically update itself when new "Shredder" builds are released. A few days ago, my Thunderbird was updated to version 3.0b4 (beta 4). As of 3.0b4, Thunderbird has implemented a new globally indexed search feature called Gloda, which is turned on by default. After trying it for the past few days, I decided I preferred the old search behavior. To revert to the old search behavior, go to Tools->Options->Advanced and uncheck "Enable Global Search and Indexer", and then restart Thunderbird.