Retina MBP 2015 does not recognise third external monitor I am trying to get this system to run:


Laptop lid closed.
1 Monitor connected with DVI-miniDP adapter to a thunderbolt port
1 Monitor connected with DVI-miniDP adapter to a thunderbolt port
1 Monitor connected with a DVI to HDMI port on the HDMI port.


I can only get the notebook to recognise 2 of these displays. I can get the third display to work, only if I disconnect an existing one.

Interestingly, if I replace one of the DVI-miniDP displays with a VGA-miniDP adapter on one of the TB ports, then all 3 displays work. Yet I don't want to keep a displayed with VGA (for obviously limitations), so I was wondering if some can provide some pointers on how to make this setup work correctly.

Running 10.10.4
It depends which MacBook you have. The cheaper ones only have integrated graphics processor (Intel Iris Graphics 6100) which runs from your CPU. The expensive ones have a separate graphics card (AMD Radeon R9 M370X) with 2Gb memory which supports more display or higher resolution displays.

Macbook with integrated Intel graphics:

Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 3840 by 2160 pixels on up to two external displays, both at millions of colors.

Macbook with AMD graphics card:

Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 3840 by 2160 pixels on up to two external displays, both at millions of colors.

Source: Apple MacBook Pro Retina specs - Graphics and Video support