For the record and in answer to
"LL, can you be more specific when you say "shuts down the Apogee Quartet" when selected."
Logic message would say "removing Quartet" and would revert to the internal speakers & mic.
The Apogee would switch off until the computer was restarted. Once restarted the Apogee would work with other programs - Garage Band, iTunes - but would repeat the same problem with Logic whaen you tried to select it in core audio,
The good news is that It Works Now!
I removed com.apple.logic.pro.cs and com.apple.logic.pro.plist (which re-appears after starting Logic again)
S, I'm really happy, thank you!
Just for your information...
The com.apple.logic.pro.cs file is the control surface preference file. Evidently it either was corrupted at some previous time or Logic saw the Quartet hardware as a control surface and set it up incorrectly. If it happens again you can disable the control surface function by going to the upper left Logic Pro drop down menu, it's under Preferences/Control Surfaces the selection is: Bypass All Control Surfaces
Just to clarify for people reading this.
The problem started when I tried to aggregate 2 Apogee Quartets together (which you should be able to do).
In hindsight I think maybe I should have quit Logic before doing the set up on Apogee Maestro. I haven't tried setting it up again since the incident.
Anyway, it's all working for me now after following the above advice.
Many thanks to Pancenter.
That's interesting. I can't find any statements like that on the Apogee website.
Can you post a link?
You are appreciated.
Apparently Apogee has changed their mind about this in the last year, so I stand corrected.
(OS 10.7.xx or above required)
Even though it references Duet-2 it lists all compatible devices (Quarted includes) at the end of the article.
That said, many Logic users have previously had problems trying to Aggregate Apogee devices, perhaps this has changed?