Dual HDMI 4k displays need sequential connect

I have a 2020 MacBook Pro, the TBT3-UDZ, and two identical 4k monitors attached with HDMI.

When I unplug the MBP from the dock and reconnect to it, only one of the displays works. In order to get both displays working, I have to unplug the second display from the dock, unplug the MBP from the dock, then connect the MBP to the dock (giving me the first display), then reconnect the second monitor. There are a few variations of this dance that are required whenever I disconnect the MBP.

Once my MBP recognizes both displays, works well – until I again disconnect from the dock and I have to repeat the process.

The unrecognized display reports that it has no HDMI connection.

Please advise on how to correct this problem so that simply reconnecting the mbp to the dock results in the prior screen arrangement working

Thanks for reaching out! We’d received and have already replied to your email that was sent to us directly. However, I’ll repost the email we’d sent here for visibility:


Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

We are currently aware that some users are seeing issues like this with displays not being detected/waking from sleep, and other manufacturers are as well. We’ve found the issues and solutions (if available) can vary depending on which MacBook model and version of macOS is used. As an example, Belkin has posted a notice for a similar problem affecting several of their docks where the system won’t detect the second display if waking from sleep.

To better understand the specific issue you’re having, when disconnecting and reconnecting the dock, is the laptop usually open and running when this is done, or is it closed in sleep mode, off, etc?

We have a troubleshooting tool that helps us find out what is going on in situations like this. Please plug the dock with your devices attached to it into your computer, then go to this page and follow the instructions there:


Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry
Senior Engineer | Product Owner
Plugable Technologies

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