To disable the SpotLight service in Mac OS X, do the following:
Mac OS X 10.4
Open a Terminal and execute the following command:
sudo pico /etc/hostconfig
Change the Spotlight line to:
SPOTLIGHT=-NO-
To remove SpotLight from the menubar, remove the file "Search.bundle" from the folder
/System/Library/CoreServices, but keep it around somewhere in case you change your mind. When you reboot the computer Spotlight will not load.
Source:
http://www.tuaw.com/2005/05/13/tiger-tips-hate-spotlight-turn-it-off/
Mac OS X 10.5
Open a Terminal and execute the following commands:
sudo launchctl unload /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
To re-enable it:
sudo launchctl load /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
Source:
http://garrettreid.com/2007/disabling-spotlight-in-mac-osx-105-leopard/
Mac OS X 10.8 Mountain Lion
In Terminal, enter the following command to disable spotlight:
sudo mdutil -a -i off
and the following command to enable spotlight again:
sudo mdutil -a -i on
(root password is required for this...)
Fix Spotlight:
Execute the command:
sudo rm -r /Volumes/SYSTEM/.Spotlight-V100 (repeat for all partitions) and restart. This should force spotlight to re-index everything...