I submitted the following on another forum and no one has replied. So, I am giving this forum a shot
I had been, for years, happily listening to music streamed through four Airport Expresses networked through my iMac and my Airport Extreme. Recently I upgraded Airport Utilities to 6.0 (and lost a lot of functionality in the process) and I upgraged iTunes to 10.5.3. The Airport Extreme and all Airport Expresses were upgraded to firmware 7.6.1. Everything worked fine until one of the Airport Expresses was taken off line (it is on a switched circuit).
I tried, in vain, to get iTunes to stream music to the Express once I brought it back on line. Airport Utility reported it was working fine and reception was excellent.
So, I unplugged another Airport Express and swapped it with the problematic one. Well, I now had the same problem with a second Airport Express. Airport Utilities reported it working fine but every time I tried to stream music to it with iTunes I got the following message:
An error occurred while connecting to the AirPlay device "Downstairs Family Room". An unknown error occurred (-15000)
Well, wanting to see if I could repeat the above, I swapped yet another Airport Express. Since it had to go off line for a little while, I now have three Airport Expresses that iTunes cannot stream music to and all give the same error when I select them in "multiple speakers" with iTunes. However, if I unplug the speakers from any of the now problematic Airport Expresses, I get the message that there are no speakers attached. I plug in the speakers and I get the "unknown error" message again.
I have no problem streaming music to my Apple TV (I am listening to musing through my Sony TV as I write this).
So, in summary, after upgrading the firmware on my Extreme and Expresses, after upgrading to iTunes 10.5.3 and after upgrading to Airport Utilities 6.0, I lose the ability to stream music to an Airport Express once it is turned off for any length of time. Currently, I can only stream music to one Airport Express, the only one that has not gone off line for a while.
I am not very upset about the glitch, because I anticipate a solution. However, I miss walking room to room and have my music streamed in 6 different rooms at the same time.
Anyone have ANY idea how to get this problem resolved?