Battling the Dreaded Black Screen in VNC

VNC is an awesome tool. It’s super fast (of course, in a local network!), and gets the job done when a plain terminal doesn’t cut it.

However, there’s nothing more irritating then seeing the dreaded black or grey VNC screen:

It is such a productivity suck and pain in the ass to deal with. I’ve had to deal with this for more than one occasion so I’m finally writing all the troubleshooting steps so that future me will thank current me.

These steps were tried on Tiger VNC on Ubuntu, but I suspect they would apply to Tight VNC and the like.

These are some steps that might help you to escape the VNC void.

1: Kill all existing VNC servers first

First do a vncserver -list

% vncserver -kill :0 # or whatever number was listed before

2: Do not use sudo to launch vncserver

Firstly, do not use sudo to launch vncserver. This creates files in the wrong permissions that would mess up non-sudo sessions. * Kill all other VNC servers first

3. Check file permissions of ~/.Xauthority

Check permissions are set to $USER for the following files:

• ~/.Xauthority
• ~/.ICEauthority

4. Is $USER logged in anywhere else?

Check that $USER is not logged in with the GUI.

5. Check ~/.vnc/xstartup

The following ~/.vnc/xstartup works. Find one which is known to work for your system.

#!/bin/sh

unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
OS=`uname -s`
if [ $OS = 'Linux' ]; then
  case "$WINDOWMANAGER" in
    *gnome*)
      if [ -e /etc/SuSE-release ]; then
        PATH=$PATH:/opt/gnome/bin
        export PATH
      fi
      ;;
  esac
fi
if [ -x /etc/X11/xinit/xinitrc ]; then
  exec /etc/X11/xinit/xinitrc
fi
if [ -f /etc/X11/xinit/xinitrc ]; then
  exec sh /etc/X11/xinit/xinitrc
fi
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
xterm -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
twm &

6. Check ~/.xsession-error for clues

This is my favorite and by far the most useful tip.

Whenever there’s something wrong with the X Window system, it gets logged into this ~/.xsession-error.

Below are some of the example error messages that helped with troubleshooting:

• xfce4-session: Unable to access file /home/benjamintan/.ICEauthority: Permission denied
• /usr/bin/x-session-manager: X server already running on display :2 xfce4-session: Another session manager is already running

Good Luck!

Hopefully, you’ll never have to encounter any VNC problems, but if you stumble upon then, I hope this is of some use to you.