usb-c triple display dock -- HDMI (4k) not working

I’m using the usb-c triple display dock with only one monitor. My laptop is the Macbook 12" (2015). The monitor is Dell U2412, which doesn’t have an HDMI input, and thus I’m using an HDMI to DVI adapter between the HDMI cable and my monitor.

If I plug the other end of my HDMI cable to the dock’s HDMI(4k) port, I don’t get a display. Interestingly, my Macbook appears to recognize the Dell U2412 display. However, if I use the dock’s HDMI-2k (Displaylink) output, the same setup (e.g. same adapter and HDMI cable) works and a proper display is shown. Similarly, the dock’s DVI output properly works.

How can I fix this? Thank you

Hi Raj,

Thanks for posting. Very unusual issue - curious to help get to the bottom of it.

Appreciate the great details on the various components in use. Wondering if the DVI to HDMI adapter is contributing to the behavior since it’s the only slightly unusual setup component. (Good to know that it works with the DisplayLink HDMI output, but wondering if it’s interfering with Alt Mode output detecting things properly.)

So a few initial quick testing suggestions:

  1. If you happen to have an HDMI to DVI cable (rather than adapter+HDMI to HDMI cable), it would be good to test with that. Removes one potential element.

  2. If you don’t have an HDMI to DVI cable on hand, would it be possible to test the Alt Mode/4K port connected to an HDMI TV to confirm functionality?

  3. Resetting the dock by unplugging power and USB for ~60 seconds is certainly worth trying in cast the chip that negotiates Alt Mode is hung up. (And though I assume it’s already been tried, rebooting the MacBook is good to try also.)

Please let us know regarding the above and we can go from there.


Thank you for the response, Gary. I will try obtaining a DVI-HDMI cable and finding a monitor with direct input.

Do you happen to know whether an adapter that specifically supports Displayport and/or alt-mode is necessary? If so, perhaps I can try finding that first.

Hi Raj,

Good questions regarding the other adapter types. Thankfully, this won’t be necessary - the dock already has a built in Alt Mode adapter. (Essentially, it’s taking the DisplayPort Alt Mode signal sent from the host, then converting it internally to HDMI.)

HDMI and DVI use the same electrical signaling, so in most cases an HDMI to DVI cable should be the most straightforward option, all things considered.

Look forward to an update once you’ve had a chance to test with a native HDMI display and/or HDMI to DVI cable.


the HDMI to DVI cable didn’t work. I’ll try the HDMI display next…

Thanks for giving that a try! I would have expected the HDMI to DVI cable to work normally since we’ve had good results testing in that configuration in our labs.

Can you please collect a set of system logs to send over when you have a moment? We have a log gathering tool here:

Please run the tool with the monitor connected to the 4K/Alt Mode port using the HDMI to DVI cable. (If results are the same with the HDMI display, feel free to collect logs with that attached instead.)

The tool will save the logs as a .zip file which can then be emailed over for us to have a look. Please email the logs to with Ticket: 144490 in the subject.

Based on what we see in the logs, we’ll advise on what the best next steps are, and at that point depending on what we see it might be best to have a replacement unit pre-tested in our labs and sent to you.

Looking forward to the logs at your convenience.


I have this same issue

Hi Shawn,

At your convenience please email and we’ll be glad to help investigate.


I have the same issue

fixed it was the USB C cable I was using make sure you use the one that come with the dock not an apple one.

Had the same issue… Was using a longer USB-C cable I purchased on Amazon and once I plugged in the one provided with the Docking station it works fine.

Hi Guys. Is there an approved USB-C to USB 3.0 cable? My HDMI 4k isn’t working either. I need a USB 3.0 cable end to plug into my laptop. I currently just bought an adapter to use but am not having any luck with it. It also is not charging my laptop too. Any help would be greatly appreciated.

Hi Shaun,

Thanks for posting. The USB-C features you mention (Power Delivery/host charging and Alt Mode video output) will only work when connected to a compatible USB-C host system.

Unfortunately these new USB-C features are not backwards compatible with USB 3.0 systems. (We do mention this on the Amazon listing and our product pages, but we’re always looking for ways to improve how we convey these types of complex compatibility details.)

Please email and we’ll work quickly with you to get the item returned to us for a full refund.


I get this same issue repeatedly and it’s only with the 4K port. I also have one DVI to HDMI adapter on one display. I wish the device had one DP port so I wouldn’t have to use that.

When I get the problem it’s always on the 4K port regardless on which display is connected to which port. Installing the DisplayLink software fixed it on the first time but only temporarily. Now I took the power off for about five minutes and it fixed it again but probably only temporarily.

Hi Jani,

Please email and we’ll be glad to help investigate.


Same issue here. Once again it’s always the 4k port regardless of display or cable. I’ve tried different monitors and cables…no luck.

Hi Bill,

Please email and we’ll be glad to help investigate.


same issue here. emailing support. using hdmi cables direct from plugable to monitors, only 2k port working.