Open the Spotlight system preference, click the Privacy tab, click the plus button, and add the volume you want to reindex. Wait five minutes, select the volume in the privacy area, and click the minus button to remove it. Spotlight will index the volume again from the ground up.

Note: Before reindexing the drive, repair permissions. Also, if the drive has just recently been indexed, give it another day or so before reindexing. It’s possible that Spotlight hasn’t completely finished indexing the drive even though you’re allowed to use it.

Again taken from Macworld...

You can also force Spotlight to index using command line. In Terminal,


man mdutil
to get man pages for it, or


sudo mdutil -E [harddrive]
where you can drag the hard drive to the terminal window, replacing all [harddrive] with what ever the name of the drive is, no []s.