After installing Leopard on my MBP I noticed that Mail wouldn’t allow me to do “Entire Message” searches. The “Entire Message” button was greyed out.

I tried rebuilding all of my mailboxes in Mail and forcing an index by calling:

    mdimport ~/Library/Mail

Neither helped.

It turns out the MBP’s boot drive had somehow been added to the Spotlight Privacy list…

D’oh!