Big Sur issues USB-C 4k ONLY the HDMI port is working

Good afternoon,

I’m having issues with My USB-C 4k docking station with my new MacBook Pro (model UD-ULTC4K).

I have two ASUS VA24E monitors plugged into the docking station. It doesn’t matter which one is plugged into the HDMI port, the monitor that is plugged into a DisplayPort returns the HDMI no signal. While that was the initial problem, now the ONLY port working on this docking station is the HDMI port - everything else is not recognized.

The docking station and monitors are both using the manufacturer supplied cables. Monitors worked with my iMac as recently as 2 weeks ago when iMac died. Previously, I successfully used both with the HP and docking station my former employer provided.

I have two different DisplayPort connectors that have worked fine, they were purchased 5 months ago when I purchased the monitors. All worked with this dock upon initial use.

The issues I am having began 4 days ago, 3 days into use.

  1. When returning to the computer after everything has been in sleep mode, one monitor will wake up, the second indicated HDMI signal not found until I opened the MacBook Pro.
  2. Even though the monitor indicates ‘signal not found’, when using my mouse, I have to scroll from Screen 1 through Screen 2, the one indicating signal not found. I cannot see the mouse for several scrolls across my desk before the mouse reappears on the Macbook Pro screen (right side in my configuration when the Macbook is open).

I didn’t think to capture screen grabs at the time to show that in System Preferences > Display > Arrangement, the MacBook Pro recognizes that there are two monitors connected while the monitor is indicating no signal. Once I unplugged and replugged into the same DisplayPort, the issue resolved.

  1. The issue then escalated to requiring switching the port used. If I used the top port, the monitor resumed only when I plugged the monitor into the bottom port. If the bottom port was used, the monitor resumed only when plugged into the top port.
  2. Approximately 48 hours later, this problem went from only occurring when waking from sleep mode to the DisplayPort screen randomly crapping out in the middle of use. Kind of difficult to save my work when the primary died and I couldn’t get to my menu. Opened Macbook Pro, unplugged everything, peripherals and all, then plugged back in. Went from 1 or 2 times a day to 5-6 times a day. Each time eats a half hour of time. Also tried restarting the M1 to resolve the issue, but this was an inconsistent fix.
  3. Another interesting thing that now happens. These monitors go from orange (sleep) to blue (on). I’ve become accustomed to just pushing the power button to reactivate from sleep mode, as this had been the case with the iMac AND the HP docking station I was using. For the past five months, these monitors have toggled between sleep or on. I had to hold the power button down for 5 seconds to turn them off. Now each defaults to off.

Currently, the second monitor is in sleep mode until I press the power button, which turns it off. Then I have to press it a second time to turn it back on.

  1. Which brings me to now. Monitor craps out in the middle of use about an hour ago. I run through this whole routine and NOTHING is bringing this second monitor back into use. Unplugged everything from both monitors. These are manufacturer supplied power cords and HDMI cables that are clearly working, because I have swapped out which monitor is plugged into the HDMI port.

I seriously doubt that two HDMI to DisplayPort adapters have died at the same time, especially given the issues that have been occurring with this docking station that has been used FOR LESS THAN A WEEK.

  1. Out of curiosity, I brought out my Apple USB-C to Digital AV adaptor I purchased with the MacBook Pro and when plugged into USB-C port of the back of the station, it doesn’t recognize the monitor, either BUT when I unplug everything else, then plug only that USB-C to Digital AV adapter into my Mac, it recognizes whichever monitor is plugged into it. However, in doing this, I realize that none of the ports work EXCEPT for the HDMI in. My mouse, my headphones, my external hard drive - none of them are recognized.

  2. I’m currently in the process of updating to Big Sur 11.2.3, in the hopes that this may have a resolution. I fear that there is something preventing the docking station from using the DisplayLink software. Also going to see if there have been any plugable Firmware updates since I checked Monday night as soon as I post this.

UPDATE: Did that help? Of course it didn’t.

I’m more than mildly peeved that this is purported to be a plug and play solution that is rapidly requiring as much time as it did for me to try to find out why the DisplayLink software wasn’t delivering on the promised second monitor capability when I installed it (15 hours on that before finding that there is a conflict with some machines preventing users from uninstalling an earlier DisplayLink version).

I purchased this product to remove my headaches with multiple display woes with the M1 Macbook Pro, but I’ve got a big one right now. I’m extremely thankful that I am somewhat tech savvy, because anyone who doesn’t do troubleshooting on the regular is probably struggling right now.

This product promises ‘you can use three monitors with your M1 Macbook Pro’ that isn’t happening. Apple tells me it will be 3-4 weeks for a MacMini with the ram and storage I require. I believe them, because it took 6 weeks to get the Macbook Pro configured with those same requirements.

So, beyond the ‘unplug everything for a minute’, try a different Displayport, try a different port (which really isn’t an option, unless you want to send me a hub with two HDMI ports), and updating my software/firmware, what else is there to do about the blank screen that I need to do the job that pays my bills?

Hi Suzanne,

Thanks for posting!

Firstly, I appreciate the detailed writeup here, despite all the frustrations you’re seeing with your UD-ULTC4K dock. I’d like to all that I can to help.

Based off the issues you listed, we could be dealing with faulty hardware with the dock, given the DP outputs, mouse, headphones, and external hard drive are all not working properly.

Could you please reach out to us at with your Amazon Order ID? Please include “Ticket #337375” and in the subject line so we can match up this post with the support ticket.

We’ll confirm purchase information and move forward from there.

Thanks for giving us a chance to help!


Thank you, Mitchell.

I create technical instruction and training materials, so I’m used to providing step by step details. Also prefer saving time by telling you what I’ve already done to troubleshoot the issue myself. My husband chuckled when I lamented that I didn’t get a screencap of the System Preferences showing three monitors, because I’m all about visual documentation. (85 screens into building an intro to MS Project Professional course for work, about 600 screen caps in this bad boy - I NEED two monitors!)

I’ll send that email out ASAP. Down time is bad, need to get the replacement quickly.

As an update to this thread, Suzanne reached out to us directly and we moved forward with a warranty replacement given the problems reported.

Upon receiving the replacement, Suzanne confirms that the new unit is working as expected!

I’ll be closing this thread, but for any other questions or concerns, please do not hesitate to open a new topic or reach out to us at We’re glad to help.

Best wishes,