External Monitors turn on and off when MacBook Pro lid is closed

[VinnyB]

When I close the lid of my MacBrook Pro, my two external monitors connected to the Dock turn on and off every few seconds. This problem does NOT happen when the lid stays open - it only happens when I close the lid on the MacBook Pro.

I have the Plugable UD-3900. My MacBook Pro is the Mid-2014 MacBook Pro running MacOS 11.4. I do not have any trouble when the lid is open, but I want to be able to close the lid when using the external monitors.

I have already followed all of the directions from other posts (specifically, changing the power option settings to not put the computer to sleep when the lid is closed).

I have also completed the “DeBug” process and have the following ticket open: #370815.

Please advise.

Thanks!

Vinny

[RichardA]

Hi Vinicius,

Thanks for reaching out to Plugable support! I’d be happy to help with that.

Clamshell mode (lid closed) is supported on computers using Apple M1 silicon with external power connected (e.g. Apple macbook power adapter) on macOS Big Sur version 11.1 and later.

I hope this is helpful,

Richard A
Plugable Technologies
https://plugable.com/support

[VinnyB]

Hi Richard,

Thanks for the information. To confirm - Clamshell mode is only available to computers using Apple M1 silicon, and not to any other Mac? Meaning, I am not able to take advantage of this mode while using the Pugable dock unless I have a computer with Apple M1 silicon?

Thanks.

[RichardA]

Hi Vinicius,

Thanks for the update.

For clarification Clamshell mode should be available for Intel based (macOS 12) and M1 based (macOS 11) Mac laptops if connected to an external power source must be connected to the Mac.

I hope this is helpful,

Richard A
Plugable Technologies
https://plugable.com/support