spacedesk is a multi-monitor app that creates virtual display screens.
You can duplicate your main monitor screen to multiple spacedesk viewers connected, just that Windows Display Control Panel/Settings user interface does not support it. This applies to spacedesk and all other displays.
We suggest the workaround steps below to mirror your main monitor to all spacedesk displays.
1. connect your 3 spacedesk viewers, so the setup will be something like this:
— Screen #1 – main monitor (1920×1080)
— Screen #2 – spacedesk viewer 1 (1920×1080)
— Screen #3 – spacedesk viewer 2 (1920×1080)
— Screen #4 – spacedesk viewer 3. (1920×1080)
2. Open spacedesk Driver Console and enable Videowall mode
3. Assign all clients connected to Video Wall.
— You will see on Connections -> Active (2 connected), 2 spacedesk clients connected, click one of them, then click the Videowall tab in the right panel
— In Wall Index box, enter any value e.g. “1”, then it will create a Video Wall1 underneath CONTROL
— Then right-click the other spacedesk clients below, then select “Assign to Wall1” and also change its dimension too
4. Change dimension of Video Wall1, by clicking it underneath CONTROL, set the Size (Width:Height) to 1920 : 1080
5. Open Windows Display Settings, and you will see an extended display (this is the videowall 1), switch it to Duplicate the main display.
You can do it via Display switch (Windows logo + P hotkey) then select Duplicate.