View Full Version : [xubuntu] Unable to run Synaptic GTK-WARNING cannot open display

April 19th, 2013, 09:26 PM
I have an intermittent problem trying to use Synaptic

As an ordinary user:

Select Applications Menu -> System -> Synaptic Package Manager.
I get prompted for my password, but then nothing happens, Synaptic doesn't start up.

The relevant piece of my /usr/share/applications/synaptic.desktop is
Exec=gksudo synaptic

Also a lock file ~/.gksu.lock gets left in my home directory.
No relevant messages in ~/.xsession-errors or in /var/log/Xorg.0.log

​As root:

# synaptic

I get the error message

No protocol specified
(synaptic:3456) Gtk WARNING: ** cannot open display: :0.0

and synaptic doesn't run.

None​ of the usual fixes work

ln -s /home/<real user>/.Xauthority /root/.Xauthority
or export XAUTHORITY=/home/<real user>/.Xauuthority
or xauth merge /home/<real user>/.Xauthority
or export DISPLAY=:0.0

Curiously, rebooting usually solves this intermittent problem.
After a reboot I can run Synaptic as an ordinary user or as root.