Why does this happen?
When connecting to a headless/virtual Windows computer, you may notice that the list of resolutions in Display Settings is limited to a maximum of 1024 x 768 or 1280 x 1024.
This is a limitation of Windows - since it cannot detect a connected display, a limited selection of "safe" resolutions is offered.
Is there a way to avoid this issue?
There are some methods to work around this.
Connect a display emulation device to the VNC Server computer
If you are connecting to VNC Server on a physical computer, you can connect an EDID emulator to the VNC Server computer. An example EDID emulator can be seen here
Note: RealVNC have not tested this particular emulator and it is only provided as an example
Configure Windows to use a different resolution
It may be possible to force Windows to provide a specific resolution. This is usually only possible on desktop computers.
PLEASE NOTE: The below option involves editing of the Registry, and should only be attempted on a non-production/non-critical machine, before rolling out to your production environment. We recommend backing up the Registry prior to making any changes.
Manual method
In this example, we will be setting a resolution of 1920 x 1080.
- Open Regedit
- Navigate to
HKLM\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration
- Select the key(s) that start with the name
SIMULATED
(orNOEDID
ifSIMULATED
does not exist) and then select the child key named 00 - Change the value
PrimSurfSize.cx
to the desired horizontal resolution (1920). Be sure to select 'Decimal' when changing these values. - Change the value
PrimSurfSize.cy
to the desired vertical resolution (1080). - Select the child key of 00 also named 00.
- Change the value of
ActiveSize.cx
to the same horizontal resolution as before (1920). - Change the value of
ActiveSize.cy
to the same vertical resolution as before (1080).
After a reboot, the simulated display should now be at the resolution you set.
This method was sourced from https://superuser.com/questions/990398/setting-display-resolution-beyond-1024x768-with-headless-windows-10)
Comments
Please sign in to leave a comment.