Repairing a faulty Spotlight index
From Mac Guides
To repair a faulty Spotlight index, take the following steps
- Open System Preferences and click Spotlight
- Click the Privacy tab
- Drag a folder or hard drive list into Spotlight window
- Remove the folder or hard drive that was just added
This will cause Spotlight to clear the existing index and begin re-indexing the folder or hard drive.
Note that you may only be able to drag folders into the privacy panel if they reside on Macintosh-formatted (HFS+) disks. Doing so with Windows (FAT, NTFS) disks is not yet supported. Additionally, if Spotlight is currently "busy", you won't be able to add folders. Check the Activity Monitor for mdimport.