TBT3-UDV and 2020 Mac Mini Display Issue

I just bought a TBT3-UDV for my 2020 Mac Mini (M1) with the hope that I could use it to drive a second monitor. I’m using the DVI to HDMI converter that came with the system. My problem is that the second display (driven by the TBT3) does not come on immediately when the Mac is turned on. The AppleOS sees that there is a signal and thinks that it is displaying, but nothing appears on the monitor. Sometimes, after a few minutes, the second monitor will get the signal and will start working as expected. I’ve swapped the monitors, which are really two Samsung television monitors, and the problem follows the TBT3 cable. I have read that Apple is having troubles with second monitors and their M1 chip line, and I don’t know if this is related. I’m also wondering if I should have bought the Pluggable USBC device instead. Do you have any advice on how I might troubleshoot or resolve the problem.

Hello Tony,

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

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 M1 Mini, then go to this page and follow the instructions there:


This will let us get a closer look at what might be happening, and then we can hopefully make some suggestions.

When emailing us the resulting diagnostics file, please mention ticket 351927 in the subject line, don’t post the results here!

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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