Why isn't search working in Finder? In Finder, the search bar in the top right corner has ceased to function. Observe:



Obviously, there should be something with the letter "s" in it. But no results appear. It's just blank. Anything I search for, anywhere I search for it, it all fails.
Other than your Finder having jaundice, this should be a simple fix. The following command will clear the volumes local store and rebuild it if necessary; Open up Terminal and type:

# sudo mdutil -E /



You will be asked for your password, provide it, as this command
requires administrator privileges to run.
After confirming your Spotlight index will be re-built and your files
should appear in the search. ( Depending on the size of your HDD it
can take a while )




To check if all volumes have indexing enabled or disabled use:

# mdutil -s -a


To toggle (enable/disable) indexing on all volumes: 

# mdutil -a -i


These commands are safe to use when/if you encounter similar issues as described in the question.



Complete options available:

 -p  Spotlight caches indexes of some network devices locally.  This option requests
     that a local caches be flushed to the appropriate network device.

 -E  This flag will cause each local store for the volumes indicated to be erased.
     The stores will be rebuilt if appropriate.

 -i on | off
     Sets the indexing status for the provided volumes to on or off.  Note that index-
     ing may be delayed due to low disk space or other conditions.

 -s  Display the indexing status of the listed volumes.

 -a  Apply command to all volumes.

 -v  Print verbose information when available.



mdutil(1) Mac OS X Manual Page