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macosxhints.com - 10.4: Completely disable Spotlight

As the previous poster said, first modify /etc/hostconfig to read:
SPOTLIGHT=-NO-
Then to get rid of the existing index, run these two commands from Terminal:
mdutil -i off /
mdutil -E /
The first command disables indexing on the boot volume, and the second erases the existing template. You can then use Activity Monitor to kill any mds or mdimport processes or else just reboot. Futzing with permissions will probably break OS updates that try to update files in the zeroed-out directories and of course won’t survive a repair-permissions run.
If you later change your mind and decide you want Spotlight after all, it’s easy to reactivate. Set

SPOTLIGHT=-YES-
in /etc/hostconfig, run in Terminal:
mdutil -i on /
and reboot.

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macosxhints.com - 10.4: Completely disable Spotlight
]