MBP 2017 / Mojave 10.14 / DL 5.2.1 - Cn't extend monitoras

[HeneryH]

That dock does support video over USB-C as it works with my Lenovo to the two display ports already. Not sure the language that is uses but DisplayLink over USB-C is a thing.

And it is displaying now from my MBP. Just in mirror rather than extend.

[AlbanRampon]

Yes, and you will not be able to extend with that product on the mac.
DisplayLink is different from DisplayPort Alternate Mode.

[HeneryH]

Does anyone know the technical reason that Win10 laptops with a Thunderbolt3 output can use this dock to extend two external monitors while OSX can't?

Or secondarily, what is the technical reason OSX CAN display to two in mirror mode but not in extend mode?

[rboerner]

Originally Posted by HeneryH

Does anyone know the technical reason that Win10 laptops with a Thunderbolt3 output can use this dock to extend two external monitors while OSX can't?

Or secondarily, what is the technical reason OSX CAN display to two in mirror mode but not in extend mode?

My impression based on the specifications of the dock (https://support.lenovo.com/us/en/solutions/acc100348) is that the unit has an internal DisplayPort MST hub inside the unit in order to facilitate the multiple display support (note that 'DisplayPort' is not the same as 'DisplayLink').

DisplayPort MST hubs are not supported in macOS. When such devices are connected to a macOS system, the behavior is that all displays connected to the DisplayPort MST hub will 'mirror' each other, as you describe.

In short, the problem appears to be the internal limitation of macOS.