macOS Big Sur - No clamshell mode...

[Zimdog]

Originally Posted by rboerner

You do not provide much detail about your specific setup, however on the surface there are differences as compared to the other post which references the CalDigit dock.

Presuming for the moment that this is the dock you are using --> https://www.kensington.com/p/product...-ivga-windows/

That docking station does NOT provide power to the host laptop, which is a key element of the requirements Apple provides for closed-display mode to work.

Further to this, you do not mention if the Apple Mac laptop you are using has an Intel processor or Apple M1 processor.

The details matter in this specific case, because at this time closed-display mode (clamshell mode) is not supported on Intel-based Macs when only a 'pure' DisplayLink-based device is connected to the host. Closed-display mode is supported on Apple M1-based Macs as long as there is a power source connected.

Thanks, and my apologies for the delayed response... but to your points:

1) I have a MacBook Pro (13-inch, 2020, Four Thunderbolt 3 ports) with an Intel processor and I'm using the Kensington USB 3.0 Dual Display Docking Station for Windows, Mac OS, Surface Pro & Surface Laptop (K33972US). The MacBook Pro is connected to external power in addition to the dock. The dock provides connection to my keyboard, mouse, external drives, USB camera, microphone, speaker, Ethernet and two Philips 246E monitors.

2) As to the supply of power, you are correct that the dock is not supplying power. However, the link you provided in a previous post no longer leads to the original page (HT201834) - and the page that it redirects to does not include information about clamshell requirements. That said, I believe these are the requirements (Search support.apple.com for "closed lid" requirements):

Check requirements
To use closed-display mode with your Mac notebook, here's what you need:

• An AC power adapter or an external display that provides power over USB-C or Thunderbolt 3 (USB-C).
• An external keyboard and mouse or trackpad, either USB or wireless.
• A USB-C to USB adapter or cable if you're using a USB mouse or keyboard with a Mac that has USB-C ports.
• An external display or projector.

You'll note that these requirements do NOT specify that the dock provide power - only that there be an AC power adapter OR an external display that provides power. So I believe this point is moot, as my Macbook Pro IS connected to external power, in addition to being connected to the dock.

3) Lastly, I'll note that clamshell mode WAS working with this configuration prior to the release of BigSur.

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Hopefully this clears up the questions regarding my setup - but even so, it's still the case that clamshell mode is not working.

Charlie

[ordep81]

New Mac user here, I have dual monitor set that I would like to use for work on my 2020 Macbook Pro (intel) have it all hooked up through the dock. Once i place the laptop in clamshell mode the video on my monitors intermittently drops to where I have to keep the laptop open and takes up real estate on my desk. Is this the same issue that most are experiencing here? Are there any workarounds like using "Amphetamine" app as others have mentioned that have had any luck?

[ordep81]

Quick update, I got a workaround on this by using Amphetamine free app, I just mirror on monitor to the laptop and the other monitor as its own. This works how I wanted.

[TheNickGuy]

Just use the legacy driver 5.2.5 and Clamshell mode will work, every driver newer than 5.2.5 does not work in Clamshell (closed) mode

[nyne87]

Just to report my success, I updated to macOS Monterey beta and the issue was resolved. I now have clamshell mode using the latest DisplayLink beta drivers for Monterey.

[Speedy]

I have the same issue that the clamshell-mode was not working any longer when i updated my mac from 10.14 (Mojave) to 11.5.2 (Big Sur). I'm using a Kensington Dock SD4780P with 2x 4K-Samsung-Screens connected via HDMI.
Actual Work-A-Round is to use Amphetamin as mentioned in the thread before.

A much bigger problem for me is, that my network-connection is interrupted for just seconds multiple-times per day, what makes remote-working with VPNs or in Virtual-Machines a nightmare.