I'm doing a project with a Pi 4B, the official touchscreen and the latest version of Raspberry Pi OS. I would like to connect to the Pi via VNC (RealVNC Viewer on Windows 10) at a higher resolution for development work.

I've enabled VNC in raspi-config, and it works perfectly when I use just the IP as the client address - the only issue is that it's fixed to the resolution of the touchscreen.

When I create another VNC server with vncserver -randr=1920x1080, I can connect to it on [IP address]:1. But I've found two issues (so far):

  • I get this error when I log in:

    GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication
    agent already exists for the given subject
  • The mouse cursor isn't correct - it's just an 'X' and isn't context sensitive.

The usual solution for the first issue (Untick "LXPolKit..." in Desktop Session Settings) doesn't apply here - that option isn't there. I have no idea how to fix the other issue.

Any idea how I sort these things out? I don't understand why the two VNC servers are behaving differently.

1 Answer 1


You can fix the black X issue with (I set my Pi's up with a script that is stateful and persistent through reboots)

# Fix the Black X problem
sudo cp /etc/vnc/xstartup /etc/vnc/xstartup.custom 
sudo sed -i 's/xsetroot -solid grey/xsetroot -solid grey -cursor\_name left_ptr/g' /etc/vnc/xstartup.custom

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