I tried to use VNC (remote desktop viewer) on a computer that does not have a monitor but failed. When that computer has a monitor, VNC viewer works fine. Also in both cases, ssh remote access works fine.

Could anyone advise me what to do? Is it required that the computer must be connected to a monitor in order for a VNC viewer to access it?

  • 1
    And how did it fail? Failed to connect? The screen was all black? You found it sleeping with the town drunk? Commented Jul 1, 2011 at 20:20
  • I bet it is the last one because it failed to connect as if the service got drunk and is not running.
    – lcb
    Commented Jul 1, 2011 at 20:25
  • that is very odd you should test further, if you have a connection then disconnect the monitor, does the connection die? If you pull the power out of the monitor when you're connected, does the connection die? if you turn the monitor off, does the connection die?
    – barlop
    Commented Jul 1, 2011 at 22:17
  • Hmm, @barlop you may misunderstood my question. I am using a remote desktop viewer (VNC on Ubuntu) in computer B to access computer A. When comp A has monitor I can view A desktop remotely from B, but when A has no monitor I can't view A desktop remotely from B. In both cases, ssh connection from B to A is good.
    – lcb
    Commented Jul 1, 2011 at 22:42
  • @lcb yes I understand the remote computer is the one you speak of as being with monitor or without monitor in your tests. I'm saying try removing the monitor while connected, and see what happens. It'd allow you to be absolutely sure that this odd phenomenon is taking place, and the nature of it. added- it seems that won't be so necessary.. kobaltz has an answer there
    – barlop
    Commented Jul 2, 2011 at 14:21

4 Answers 4



add the above line to /boot/config.txt in raspberry OS or /boot/firmware/config.txt in ubuntu on rpi4


On my I could set the RaspPi to composite. Here is how. On the RaspPi click the RaspPi icon > Preferences > Raspberry Pi Configuration > Display > Composite Video = Enable. I came across this by shotgunning so I don't know what else it does. The HDML is disabled so you'll need to VNC to change it back.


I had the same problem, and after doing some research, I found the simplest solution to be a hardware one: I got one of these HDMI dummy plugs. It fools your system into thinking a monitor is connected. Less than $10, and worked like a charm.


This worked for me. Basically cli into the OS. In my case Raspbian run raspi-config and change resolution. I changed mine to 1024x768 and it worked. Others have said they had to go to 1280x768 to fix.


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