Display on to apple tv in closed clamshell mode?

Clamshell mode is only applicable when you actually have an external display physically connected to your Machine. Thus, Airplay Mirroring is not supported, natively, by Apple's clamshell mode. There is third party software purported to make this work, however.

NoSleep Extension by Pavel Prokofiev

I've found that even when I have an external display physically connected to my macbook pro in clamshell mode, I'm still not able to airplay to my apple tv. Well, I can but it just shows a frozen image and I have to reboot my mac by manually powering off. So basically, if I'm happily working in clamshell mode with an external monitor, and then I want to airplay to my apple tv, then I have to open up my macbook pro display and leave clamshell mode first, then turn on airplay. In my experience. It's a bummer having to remember to do that every time, or else your system freezes.

oregonjoe,

Have you read thru this:

How to use your Mac notebook computer in closed-clamshell (display closed) mode with an external display - Apple Suppor…

Yup. I have no issues using an external display in clamshell mode. It's only when I try to airplay to my apple tv while in this clamshell mode that I run into problems. So to clarify, there are 3 devices in my situation: my macbook, my external monitor, and my apple tv (which is connected to my hdtv of course, so 4 devices). Usually I just use my external monitor with my macbook closed. That works fine. But when I occasionally want to airplay to my apple tv as additional mirrored/extended monitor, I have to open up the macbook first to exit clamshell mode. Otherwise if I just go straight into airplay while still in clamshell mode, my hdtv shows a frozen image, my external monitor goes black and I have no choice but to manually turn off my macbook. Hope that makes sense. I think it would be easier if I could draw a diagram haha.

Yep, need to go to system prefs to change the display.

I know of no other way, maybe someone else will chime in with a work-around.

Best

Hmm not sure what you mean by "go to system prefs to change the display." What display settings need to be changed there? What will that allow me to do? Right now, like I said my workaround is to just open up the macbook (exit clamshell mode) before activating airplay. This works fine and is not a big deal. But like I said, it's just annoying to have to remember to do that every time.