There is nothing unusual in my set up that I know of. This morning my MacBook (which sync to the same settings through Dropbox) has started doing the same thing. Two days ago it worked, today it doesn't. No changes to the settings on either machine. iMac running 10.9, MacBook running 10.8.
The only thing that I have done is force a reindex of Spotlight on the iMac.
I'm afraid I don't understand how to follow Andrew's post. I don't know where the address book metadata folder is to be able to drag anything from it.
Help much appreciated - this was the single most used feature of Alfred.