I ran into an interesting issue where for the first time in a while, Spotlight wasn't finding what I knew existed within my emails. Each time I have to do expense reports (which I just LOVE doing!), I rely on Spotlight search to find my specific airfare, rental car, and hotel receipts that are sent to me via pdf within email messages.

After some googling, I found a method that did the trick:

Enter the following in Terminal:

sudo mdutil -E /

You'll be prompted for your passord and then the index rebuilding process will begin.

After the reindexing was complete, everything worked perfectly. Thanks Hoffman Labs!

Onyx is a great free app that helps in several ways (including rebuilding indexes).