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[SOLVED] MBP mid-2012 2nd monitor is mirroring the first

Alex Mck

Distinguished
Sep 18, 2013
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I'm currently having problems connecting two monitors to my mac. What normally occurs is one monitor just mirros the other leaving me with my laptops screen a monitor and a monitor mirroring the 1st monitor. I'm using a mini display port to dual hdmi and at the time it seemed like the perfect solution. One hdmi slot per screen.

Does anyone have any idea on what I can do so that I can have all monitors acting independently and not mirroring?

Specs:
Monitors
BenqXL2411tz
Aser g-sync 1440x2560

Connection cord:
Alogic Mini DisplayPort to Dual HDMI Adapter - 4K - 30 Hz

Its got a intel 4000 which should be more then capable of displaying content on two separate screens
 
Solution
The pre-retina Macbooks only support one external display. You have to use a USB adapter or some thunderbolt dock for two displays. They have to be one which uses a Mac compatible GPU. These are really low end ones in these devices. Suitable for office work.

Even for new MacBooks. MacOS doesn’t support MST, at least most of the time. Which that adapter likely uses. So that likely won’t work on them either. This is an OS issue. As MST works in Windows in Bootcamp.

macOS needs to use two ports for two monitors. I think there are a few docks and monitors which support Daisy chaining over DisplayPort (MST) in macOS.
The pre-retina Macbooks only support one external display. You have to use a USB adapter or some thunderbolt dock for two displays. They have to be one which uses a Mac compatible GPU. These are really low end ones in these devices. Suitable for office work.

Even for new MacBooks. MacOS doesn’t support MST, at least most of the time. Which that adapter likely uses. So that likely won’t work on them either. This is an OS issue. As MST works in Windows in Bootcamp.

macOS needs to use two ports for two monitors. I think there are a few docks and monitors which support Daisy chaining over DisplayPort (MST) in macOS.
 
Solution