displaythunderboltthunderbolt-display
I am trying to run two thunderbolt displays with my macbook pro and it will only run one at a time.
I have tried the displays with an older 17 inch model and it runs all three (including the internal screen) fine.
Yes, Flawlessly!!!! in the image there is a lie the 2560 x 1080 is not 34-inches is 25-inches and that one is connected trough display link usb-hdmi adapter from toshiba, the 3440 x 1440 is 34-inches but you need thunderbolt cable, the macbook air early 2014 can run them both! Super happy!!! to the toshiba adapter I can even plug another 1920 x 1080, so I wonder if through daisy chain it can run two 34 inch... well the answer is yes!!
It looks like your computer can only drive up to two external displays (officially, at least). https://support.apple.com/kb/SP703?locale=en_US
Best Answer
I think it's that my laptop is on the edge of being powerful enough for both.
I made some space on my hard disk, stopped any applications from opening automatically on login and restarted whilst plugged in to both monitors.