Dual monitor problem

Discussion in 'OS X Yosemite (10.10)' started by esamuel08, Jul 2, 2015.

  1. esamuel08 macrumors newbie

    Jul 2, 2015
    Hi there,

    I recently upgraded my monitor and would still like to use the old one next to this new.

    Im using a MacBook Pro (15-inch, Early 2011) which has one Mini Display Port/thunderbolt connection. I want to use the new monitor with a display port and the old monitor with a DVI (or VGA but id rather use DVI).

    I have this - http://www.amazon.co.uk/gp/product/B005RD3X3Q?psc=1&redirect=true&ref_=oh_aui_de tailpage_o01_s00 - but it only seems to allow me to connect on display at a time. If I plug the display port and DVI into the adaptor the new monitor will work but nothing from the old one. If I unplug the Displayport the DVI monitor will flick on.

    Running Yosemite.

    Can this mac only handle one monitor at a time? Is it the adaptor to the port maybe?

    Please help it will be great to get them working together.

    Cheers, E
  2. 0d085d macrumors regular

    Apr 23, 2015
    There's a lot of confusion out there over these external displays - mostly around the difference between Thunderbolt and the Mini DisplayPort, which, rather unhelpfully, look exactly the same and serve almost the same purpose.

    This is quite a helpful document: http://support.apple.com/kb/HT4885

    What you have on your specific machine is a Thunderbolt (version 1) port. Thunderbolt allows daisy chaining of devices (including monitors), but Mini DisplayPort -> VGA/HDMI adaptors terminate this chain, meaning that you can't plug anything else in afterwards. You also can't connect a Mini DisplayPort display directly into a Thunderbolt display (for reasons unknown).

    Essentially you can only plug one display in (unless they're both Apple Thunderbolt displays) to your Thunderbolt port. The other one will have to go through a USB->VGA/HDMI adaptor. These used to be quite laggy, but I hear they're better now.

    P.S. If somebody who's physically tried this or does know of a solution that definitely works, PLEASE do correct me. I don't want to add more confusion...
  3. campyguy macrumors 68040

    Mar 21, 2014
    OP, for your Mac you can pretty much ignore the above post. We've got one of the same Macs in our office.

    I'll quote this for you from Apple's tech specs (I have them on PDFs): "Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 2560 by 1600 pixels on an external display, both at millions of colors." There's no getting around this, and the current language on Apple's Support site is identical - I checked before posting this.

    The USB drivers for DP adapters do not support Yosemite. The only two eGPU boxes that support multiple displays that I'm aware of that support Yosemite work with DVI-D displays only (Matrox).
  4. esamuel08 thread starter macrumors newbie

    Jul 2, 2015
    Late reply, I've been away.

    So from the two posts I'm still not exactly sure what I can do that.

    Are you saying that with this model of macbook pro there is no way I can use 2 external displays until the USB to DVI/VGA is working on Yosemite?
  5. cyberlily62 macrumors newbie


    Jul 12, 2015
    Hi. I recently upgrade to a Mac Pro (mid 2012) tower with Yosemite installed. In my System Prefs, Display, the "Arrangement" tab is missing so I cannot tell the computer to look for my 2nd monitor. What's up? I am missing my dual display and really need it. I'm a graphic designer power user and it is essential to my business.
    Best regards.
  6. campyguy macrumors 68040

    Mar 21, 2014
    I can't offer any input as to why your second display is not being detected by your Mac. I can offer that the Arrangement Tab will show up only if your Mac detects multiple displays - the correct descriptor is that Tab is "Hidden", not "Missing".

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5 July 2, 2015