Dell u2421e

[lakeercj]

Hi,

I have two Dell u2421e displays from work. I believe they have the dock built in. I can't seem to get my Mac m2 to extend to both, display 2 just mirrors what is on display 1.

I also have the 'Please allow your display link device' alert showing.

Is this because the u2421e is not supported or am I doing something wrong?

Thanks

Chris

[rboerner]

Originally Posted by lakeercj

Hi,

I have two Dell u2421e displays from work. I believe they have the dock built in. I can't seem to get my Mac m2 to extend to both, display 2 just mirrors what is on display 1.

I also have the 'Please allow your display link device' alert showing.

Is this because the u2421e is not supported or am I doing something wrong?

Thanks

Chris

Your two Dell displays do NOT have DisplayLink technology inside of them, which is why the DisplayLink Manager Application does not recognize any devices are detected.

Given that your displays do not use DisplayLink technology, DisplayLink will not be able to assist you.

According to the manual for your displays --> https://dl.dell.com/content/manual73...language=en-us you monitors have a built-in DisplayPort multi-stream transport (MST) hub inside of them.

Note the difference between 'DisplayPort' and 'DisplayLink', as they are two different technologies.

In brief, the DP MST hubs inside your displays allow them to be connected in series (also known as 'daisy-chained'). Page 35 of the manual for your display shows how this works.

Apple Mac systems do NOT support DP MST technology, which is why both of your displays are showing a mirror image of each other. Unfortunately there is no workaround for this behavior.

If you wish to add both Dell displays to your Mac, you will have to use a product based on DisplayLink technology. DisplayLink has a guide to available DisplayLink products here --> https://www.synaptics.com/products/d...ylink-products