The second monitor is no longer recognized

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The second monitor is no longer recognized

I connected the DELL D6000 docking station with two monitors to my Mac, but suddenly the second monitor is no longer recognized.

I can see it in Display Link Manager, but not in the Mac settings.

I’ve tried restarting the system, updating Display Link Manager, and using new cables, but nothing works.

Sometimes (not always), the bottom monitor displays the screen as shown in the photos (sometimes in low resolution, other times in high resolution), but it isn’t recognized by the Mac, so I can’t work on that monitor (change the resolution, adjust the monitor layout, etc.).

Any suggestions?

MacBook Air M4 with Tahoe. I didn’t update to a new version of macOS before the problem occurred.

MacBook Air 13″, macOS 26.5

Posted on May 12, 2026 1:10 PM

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Answer 1

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Servant of Cats

Level 8

40,013 points

May 12, 2026 1:36 PM in response to Bazarovfo

A M4 MacBook Air does not need to use a second-class workaround like DisplayLink to drive two external monitors. It can drive up to two monitors attached to a Thunderbolt dock – or one monitor through each of its two USB-C host ports.

The dock you are using with it is not a Thunderbolt dock, but is a "Universal" dock that works even with USB-A host ports. USB-A was never intended to carry video, so that's a sure sign that the dock must rely on a workaround (like DisplayLink) at least part of the time.

Dell Support – Dell Universal Dock D6000

I'm not sure how much help you will get from Dell. The Dell site does not even offer DisplayLink driver downloads for the Mac – only for assorted versions of Windows.

Synaptics is the "arms supplier" for DisplayLink. They make DisplayLink chip sets that "workaround" products like the Dell D6000 use, and make their money off selling chip sets (and/or supporting code) to manufacturers like Dell. Perhaps you can find troubleshooting tips and drivers on the Synaptics site.

Synaptics – DisplayLink Graphics

Synaptics – DisplayLink Support

An alternative might be to upgrade to a proper Thunderbolt dock, and to ditch DisplayLink.

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