Alternative Video Output Solutions for macOS 10.13.4 systems with UD-ULTCDL and UD-ULTC4K Docks

Recently we wrote about how the latest update to macOS 10.13.4 causes several different types of video devices, including those based on the DisplayLink technology we use in many of our products, to stop working. This loss of functionality is a frustrating development for those of us who have become accustomed to multi-monitor goodness as part of our daily workflow.

With this OS change, the total number of displays that can be connected to Thunderbolt 3 and USB-C Macs is now significantly reduced. Users of our UD-ULTCDL and UD-ULTC4K docks can continue to drive a single monitor connected to the 4K “Alt Mode” HDMI output on their dock. See the table below for information on the total number of monitors your 10.13.4 MacBook supports, and details on which products can be connected to a free Thunderbolt 3 port on your system to connect additional display(s) in conjunction with the monitor connected to your UD-ULTCDL/ULTC4K docking station.

For a more comprehensive look at the display support on specific Mac platforms along with additional options that aren’t based on DisplayLink technology to help ‘get back’ some displays, see additional details below.

Thunderbolt 3 MacBook Pros with AMD GPU

Apple systems that have Thunderbolt 3 ports and also have an internal AMD graphics adapter (GPU) have the most options available, as they can support a maximum of four external displays using a combination of USB-C or Thunderbolt 3 devices. An important element to keep in mind is that the one functioning display connected to the dock is included in that total number.

The most simple (and least expensive) method to add two displays is to connect them directly to the Thunderbolt 3 ports of the system using a combination of any two of our USB-C video cables or adapters (one adapter for each display):

USB-C to DisplayPort cable ->
USB-C to HDMI cable ->
USB-C to HDMI adapter ->
USB-C to DVI adapter ->
USB-C to VGA adapter ->

A slightly more expensive solution (but a one that requires the use of one less Thunderbolt 3 port) is to add one of our Thunderbolt 3 Dual Display Adapters:

Thunderbolt 3 Dual DisplayPort Adapter ->
Thunderbolt 3 Dual HDMI adapter ->

Thunderbolt 3 MacBook Pros with Intel GPU

Apple systems that have Thunderbolt 3 ports and have only an internal Intel graphics adapter (GPU) are slightly more limited, as they can only support a maximum of two external displays using a combination of USB-C or Thunderbolt 3 devices.

As mentioned earlier, the single video output of either dock that is still working counts against this total, so the only option is to add one additional display to the system using one of USB-C video cables or adapters:

USB-C to DisplayPort cable ->
USB-C to HDMI cable ->
USB-C to HDMI adapter ->
USB-C to DVI adapter ->
USB-C to VGA adapter ->

** Important note – Thunderbolt 3 Dual Display adapters cannot circumvent the total display limitations present in any MacBook Pro. The total maximum number of displays will always be in effect regardless of what types of adapters or cables are in use. **

USB-C 12” Retina MacBook (no Thunderbolt 3 support)

For MacBooks (without the ‘Pro’ designation), as the system only has a single USB-C port unfortunately there are no other options to connect additional displays beyond what is already working in the dock. Without the ability to use a DisplayLink-powered device, the MacBook can only connect to one external display.

While certainly less than ideal, depending on what Mac system you have there are options to use more than the one additional display currently afforded by the dock. While certainly not a solution for the original problem caused by the update, these other connection types can provide at least a partial workaround.

Legacy MacBooks with Mini DisplayPort/Thunderbolt/Thunderbolt 2

We have not officially supported our USB 3.0 generation docking stations and graphics adapters on Mac due to driver issues present in OS X 10.9 (Mavericks) and later. But we realize that even though we state “Mac not supported” on these products, some customers did go ahead and purchase them for use on Mac systems. For these MacBooks, a Mini DisplayPort adapter can be used for a single display. Alternatively, Thunderbolt 2 docking stations are available from other vendors.

As always, please let us know if you have any questions in the comments below or contact us directly via

8 comments on “Alternative Video Output Solutions for macOS 10.13.4 systems with UD-ULTCDL and UD-ULTC4K Docks”

  1. The Gavitron Reply

    I don’t see an MBP with the ATI Radeon listed in this table, is it the same as ‘discrete AMD’?

    I am certain I have a discrete GPU on my MBP, which is a:
    MacBook Pro (15-inch, 2017) 3.1 GHz Intel Core i7

    my display page in hwinfo reports both of:
    Intel HD Graphics 630
    Radeon Pro 560

    the radeon spec sheet is as follows:
    Chipset Model: Radeon Pro 560
    Type: GPU
    Bus: PCIe
    PCIe Lane Width: x8
    VRAM (Total): 4096 MB
    Vendor: ATI (0x1002)
    Device ID: 0x67ef
    Revision ID: 0x00c0
    ROM Revision: 113-C980AJ-927
    Automatic Graphics Switching: Supported
    gMux Version: 4.0.29 [3.2.8]
    EFI Driver Version: 01.00.927
    Metal: Supported

    Is this just an oversight in the above table?

    • Bob Boerner Reply

      The Radeon line of GPUs is made by AMD, and we have updated the table to be more specific. Thanks for bringing that to our attention!

  2. KP Reply

    My Macbook pro has Intel Iris Pro and Nvidia Geforce GT 750M? I don’t see report on this

    • Bob Boerner Reply

      Based on your description, it sounds like you have MacBook Pro 15″ Mid 2014 model -> Assuming that is in fact the model you have, the system does not have either a Thunderbolt 3 or USB-C port built-in, so it would fall under the category of “Legacy MacBooks with Mini DisplayPort/Thunderbolt/Thunderbolt 2” we mention at the bottom of our post.

  3. Andy Mejia Reply

    I have the 2017 macbook pro touch bar with Intel Iris Plus Graphics 650 1536 MB running macOS 10.13.3 i want to update my mac to the new update but im afraid it will mess up my setup with two 4k lg 27 monitors. currently have them connected as follows. one thunderbolt from macbook pro to plugable usb c 4k docking station to host. Other screen is thunderbolt from macbook pro to hdmi 4k port. Should i not update?

    • Bob Boerner Reply

      Hi Andy,

      The two DisplayPort outputs of our USB-C Triple 4K Display Docking Station (UD-ULTC4K) dock that are powered by DisplayLink technology will no longer work after the macOS 10.13.4 update. The HDMI 4K output of the UD-ULTC4K will continue to work after the macOS 10.13.4 update, as it powered by USB-C Alt Mode video (it does not use DisplayLink). Any monitor directly connected to one of the Thunderbolt 3 ports in your Mac will continue to work. Before applying the update, please reach out to us directly via if you have any additional questions.

  4. David Budde Reply

    Hi Bob,
    I have the 2016 13″ Macbook Pro with Touch bar. I was using your UD-ULTCDL-EU with 2 24″ Full HD monitors.
    Obviously, the OS update screwed that up. I’m now using a simple hdmi adapter to connect directly to one of them. However, even this is at times super buggy and will randomly lose connection.
    However, I can’t use my plugable dock anymore (only for charging and as a usb-hub). Neither of the HDMI ports works. My MB won’t recognize the screen.
    Any idea?



    • Bob Boerner Reply

      Hi David,

      The ‘HDMI 4K’ port of the dock should be working even after the macOS 10.13.4 update (as is it not powered by the DisplayLink chip), so best to send one of our PlugDebug files ( to so we can determine the next steps. If you can also include your Amazon Order ID number in your email that would be much appreciated.

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