The editor works for me, but the sound on my Mac can't be heard through my studio monitors, which were working fine under Mavericks. I used to be able to listen to music, youtube, etc with 11R on and through USB to my Mac. The studio monitors are plugged in via XLR.

Did I do something wrong? Or is it because the driver does not support Yosemite yet?

I can't test XLR output right now, but the SPDIF out will play YouTube etc, as you describe. Make sure the Eleven Rack is set "Use This Device for Sound Output" in Audio MIDI Setup. In my case, I also had to set "Digital Output" on the 11R to "Mirror Analog."

Actually - I did test the XLRs into my H4 recorder - they're outputting the Mac-generated sounds as well.

I changed the Digital Output to Mirror Analog from Rig Output just now, and set 11R as the default sound output device. It still doesn't output my Mac-generated sounds. The XLR are plugged into the Main Output on the back of 11R going straight to the monitors. I can hear my guitar no problem, it's just the sounds from my mac is no longer available.

I also opened Logic Pro X, with input and output set to 11R. It sees my guitar signal and I'm able to record but no sounds during playback. My Mac definitely sees the 11R but it just won't output the sounds as it's supposed to.

Anyone have any ideas what else I should check?

Hopefully this will help.... FIRST... go into System Preference -> Sound and find the option to "Show volume in the menu bar" make sure it's checked.

Once you do that, Option+Click on the volume icon and you can select your output device for sound.. set it to the Eleven Rack and you should be good to go. Your setup is exactly the way I have mine (XLR to studio monitors) and that is how I do it to make it work.

thanks, but it doesn't allow me to change any volume. The controls are all greyed out.

After I choose Avid Eleven Rack as the Output, the Output Volume is maxed out (and greyed out). In the middle it says "The selected device has no output controls".

It's been like that since Mavericks, but it did work under Mavericks even though everything is the same. And I used to use the volume knob on the 11R to control volume of sounds from my Mac and the guitar.

It is very strange it works for most of you but not me. =(

Odd. FYI, I installed ElevenRack_1_2_1_Mac_83290.dmg from:
http://avid.force.com/pkb/articles/download/Eleven-Rack-Drivers

And I don't have my 11R connected right now, but it is the updated/Expansion Pack-enabled. I don't know if that matters. I understand how frustrated you must be - especially since it worked before. I'm new to all of this, so can't offer much more help.

Yes I installed and re-installed the driver a couple times. I even reset my Mac's PRAM and still no luck. Yes, mine is with Exp pack.

Robitaille mentioned about changing the volume in "Sound", but mine has been greyed out for 11R since day one. Is it supposed to be adjustable? Was I missing something since day one?

I have same problem with Yosemitte ...11R editor works fine ...but yosemitte not supported pro tools 10

Hi! I had the same problem but now its working Just Fine. This its what I do.

First update the latest version of PT 11 (In my case PT 11.3 - Restart
Then UNINSTALL the 11R Drivers - Restart
Then Instal the 11R drivers Again. - Restart.

And Now Everything works perfect. I can heard the audio through the 11R (iTunes, Youtube, Etc)

NO issues at all now that I've fully crossed over to the newest OS.. no issues with drivers.. although.. it change all of my playback engine and i/o preferences.. that was fixed quick enough once I realized what it did.. it also changed my bit rate to something other than what 11R was set to.. but that came up in a dialog box when I was firing up a session and that was quickly fixed.

edited to add.. the only thing not right is that my dvd player won't play a dvd?.. weird.