Setting display resolution beyond 1024x768 with headless Windows 10?

Question

I have a Windows 10 desktop that I run headless. When I plug in a display, it correctly uses that display's native resolution. When I disconnect the display and connect to the computer over VNC, the resolution is locked to 1024x768. There are several places to adjust the resolution (classic Control Panel, new Settings panel, Nvidia control panel) but all fail with various errors along the lines of "settings could not be saved."

Is it possible to change the display resolution to something under than 1024x768 when running headless?

Answer 1

I experienced something similar when trying stream from a computer that only had network and power connected. Here's what worked for me:

1. Open regedit and navigate to HKLM/SYSTEM/CurrentControlSet/Control/GraphicsDrivers/Configuration
2. Select the key that starts with the name SIMULATED and then select the child key of SIMULATED... named 00
3. Change the value PrimSurfSize.cx to the desired horizontal resolution (1920 in my case). Be sure to select 'Decimal' when changing these values.
4. Change the value PrimSurfSize.cy to the desired vertical resolution (1080 in my case).
5. Change the value Stride, for 1920x1080 this is 7680. ((1920 * 32 + 7) / 8)
6. Select the child key of 00 also named 00 Change the value of ActiveSize.cx to the same horizontal resolution as before
7. Change the value of ActiveSize.cy to the same vertical resolution as before
8. You can change the other values in this key that are set to 1024 and 768, but I haven't noticed an impact.

After a reboot without a display connected, the simulated display should now be at the resolution you set.

Source: https://steamcommunity.com/app/353380/discussions/0/490125737470862532/