N1CKN4M3
Level 1
(0 points)
Q: Macbook Pro 15" cannot use both thunderbolt at same time
I'm trying to connect three external monitors to my Macbook Pro 15".
I connect one monitor to the HDMI, and the other two to Thunderbolt.
Only two monitors will give me a picture.
If i disconnect one working monitor, the one who was not working will begin to work.
I can change ports between the monitors and always only two monitors will be working.
I can open my Macbook and have the inbuild screen to work as a third screen.
But the external screens will only show two at time.
Why is that?
I'm using El Capitan.
I have tried the "Search display" function in settings.
I have also tried to reboot.
I have also tried to unplug the power cables for the screens.
MacBook Pro with Retina display, OS X El Capitan (10.11)
Malcolm J. Rayfield
Level 5
(7,945 points)
Yes, but two of the displays were iMacs in Target Display Mode. Maybe that makes a difference. Did you read the comments? Most could not get three external displays to work with OS X.
