All of a sudden, about three days ago, I started having this exact problem, but it only occurs with one of my speakers, not all of them. Indigo says the speaker isn't available, but Airfoil connects no problem.
If I go to the Airfoil plugin and have it list speakers, it will list the problem speaker twice (Pioneer Rcvr) with two different IDs. I reset the speaker list and it goes down to just one of them again. Then I have to reset all the action groups to the new ID. Give it a day, then I have the same problem.
So it seems like at some point, the ID of the speaker changes which Indigo picks up, but it holds onto the old ID. I dunno. Here's a copy of the log with a current speaker list, then reset speakers, then current speaker list again.
Nov 21, 2013, 4:41:49 PM
Airfoil Current Speaker List:
Speaker: Kitchen ID: 00254B06A506
Speaker: Master Bedroom ID: 20C9D0A00333
Speaker: Pioneer Rcvr ID: 4C504241434B
Speaker: Pioneer Rcvr ID: 745E1C2F184A
Speaker: iMac2011 ID: C82A1425092D
Speaker: DiningRoom ID: F0D1A907B126
Speaker: Computer ID: com.rogueamoeba.airfoil.LocalSpeaker
Airfoil Current Speaker List:
Speaker: Master Bedroom ID: 20C9D0A00333
Speaker: Pioneer Rcvr ID: 745E1C2F184A
Speaker: iMac2011 ID: C82A1425092D
Speaker: DiningRoom ID: F0D1A907B126
Speaker: Computer ID: com.rogueamoeba.airfoil.LocalSpeaker
I'm running the latest beta of Airfoil (4.8.2b2).
Been having lots of gremlins lately - seems like since I upgraded to Mavericks...
Phil
EDIT: Not sure if this could be it, but I just remembered that I've lost power to the Pioneer Receiver twice in the last week. Once during the windstorm (same night as the big storms in the Midwest), and again last night when I exchanged UPSes for the home theater setup. Would the Pioneer, if it lost power completely, be assigned a new ID number by Airfoil or Indigo?