If you have previously disabled the Mac OS X Spotlight feature and you now find that you would like to turn it on again, following these steps to do so.

1. Launch Terminal and type the following command: sudo nano /etc/hostconfig
2. Find the following entry in the hostconfig file: SPOTLIGHT=-NO-
3. Change SPOTLIGHT=-NO- to SPOTLIGHT=-YES-
4. Save /etc/hostconfig by hitting Control-O and the return key. Next hit Control-X to exit the nano editor.
6. Disable the Spotlight index by typing the following in the Terminal: sudo mdutil -i on /
7. When you reboot, Spotlight will be enabled again.

If you would like to disable the Mac OS X Spotlight feature, follow our guide on How To Completely Disable Mac OS X Spotlight.