This article is about my experience attempting to get dual-HDMI working on a MacBook Pro. After purchasing several devices, mostly without success ... I decided to document my findings.

This all started as I shifted clients, a MacBook Pro was provided.

First Attempt

I picked up a dock (USB-hub) that used two of the USB-C ports on the side. It worked great and I was able to connect to the provided external monitor.

BUT. Yes, there's a BUT. Isn't there always.

But, when I connected a video cable to the second HDMI connector in one of the client's conference rooms, it didn't work. There was a bit of crazed diagnostics that told me that in some cases, the second HDMI port did not work correctly.

Remember this issue, I'll come back to it.

There was an additional problem with this particular hardware. I quickly found out that I needed to change things up because the dock was covering half the vents on my machine. After about the third temperature-related reboot, I changed things up.

I elevated the back of the machine to optimize the airflow. Problem(s) solved, sort of.

Then, everything changed ...

Second Attempt

I got to work-from-home.

I have two monitors and a few other machines connected via a hefty KVM switch.

During this transition to work-from-home, the original dock was loaned out to a co-worker and I began using a simpler USB-hub but ran into some odd issues with the mouse, so the simpler hub got set aside and the MacBook got its own little table next to my desk that killed my back.

Things had to change ...

Third Attempt

I got annoyed that I couldn't connect this machine via the KVM to my two curved-monitors and set out to prove my technical expertise (and save my spine).

What came next surprised me a bit, took a chunk out of my ego, and this article was born.

I purchased a slightly better USB-hub from a vendor I know and respect. It stated specifically this hub could handle dual-monitors.

It did not.

BUT. Yes, another BUT.

But, I was able to get the two USB-hubs (the second and third from earlier in the article) to reliably connect to the monitors!

Things were getting ugly, having all this extra hardware wrapping around my desk. Additionally, this pretty hefty hit to my ego left me wanting to do some research, to solve this problem (there's a part of me that loves an elegant solution).

The Findings

In researching the various hubs I had been using and a few articles about this type of issue, I realized that I was seeing USB-C and Thunderbolt 3 being used somewhat interchangeably.

I dug in further and read a few articles on the history of these two standards and realized that my problem was simple. I was connecting USB-C devices to (form-factor USB-C) Thunderbolt 3 ports.

Remember that issue before that I said I'd come back to. I did eventually figure out what was going on. The screen in the client's conference room supported 4K ... the dock I was connecting to was using USB-C, not Thunderbolt 3, hence things didn't work correctly.

This all seems pretty straight forward now that I have all the answers!

Fourth Attempt

With these realizations, I went out and started more research and quickly came across a hub that should do what I want.

And it did (you need to envision me jumping up and down cheering here)!

Conclusion

Through all of this, I have been re-working my setup and layout at home. With the resolution of this issue, I can now reliably work in a much better setting; read this as my older eyes don't have to strain to see the text on a smaller screen and my back is no longer screaming at me.

I will also admit that researching my needs prior to purchasing multiple devices (possibly even asking for assistance) is something I need to pay attention to in the future.