Connecting peripherals to a laptop should be painless in 2022, right? In this short article I show you what obstacles I encountered when I wanted to connect an external display to my new M1 MacBook Pro. And how I solved the issues.

I have two machines, a Surface Pro 8 for personal use, and a MacBook Pro for the job. To easily re-use peripherals, the external display, webcam, mic, and mouse are connected to a Thunderbolt Dock (Dell WD19TB). Until recently, the MacBook was an i9. With the job, I changed it to an M1 Pro. The 16" MacBook Pro has three Thunderbolt 4 ports. Anker has at nice summary of changes between Thunderbolt 3 and 4.

So, connecting a single external display to one of the Dock ports should work, right?

According to Dell, right.

Like I said, the setup worked like a charm with the i9.

So, what was the issue?

When I connected the M1 MacBook Pro, the external display showed the screen for a few seconds, then went dark. And turned on, showing the screen for a few seconds. And went dark...

Unfortunately, the web is full of stories with external display woes on M1 machines The suggested fixes include tips like

• unplugging the cable connected to the external display and plugging it in again
• rebooting the Mac
• setting the display timeout to never

Certainly, I tried them all. None worked.

The HDMI port of the MacBook worked perfectly, and an old USB C-HDMI dongle by Apple worked, too. Consequently, the display shouldn't be the cause for the trouble. And the Dock worked with two other machines. Therefore, it must have something to do with the new Mac.

But, what to do? Buy another Dock?

The Dell Dock supports not only HDMI, but also DisplayPort. So, I decided to hook up my external display to the Dock using a DisplayPort cable. Guess what? On the surface Pro 8, things worked out of the box. On the Mac, though, the screen remained dark.

belkin has a very nice support document regarding the compatibility of their Docks with M1 hardware. To enable two external displays, they suggest installing the Synaptics DisplayLink Manager. While I would have been more than happy to just use one external display, I decided to give it a try.

Guess what? It worked.

TL;DR

If you want to use an external display connected to a Thunderbolt Dock with an M1 Mac and you face issues, try installing the DisplayLink Manager. Although there certainly is no guarantee that it'll work for you, it has, at least, for me.

https://www.synaptics.com/products/displaylink-graphics/small-office/how