Running xfce4 under vnc xfce4-session report "Another session manager is already running"

tor..@..il.com said:

I have the same problem. Can xfce4-session not be run independently on two different X displays?

It seems to be necessary to run xfce4-session in the VNC xstartup file, since simply running xfwm4 there will not give me e.g. any mouse menu in the VNC root window. But it doesn't work due to this error.

nar..@..il.com said:

Same problem here.

How to trigger the bug:

Log into a XFCE4 session on the console
start a VNC desktop with 'startxcfe4' in your ~/.vnc/xstartup
log into the VNC session and admire the blank screen

There's 1 very crude workaround I know of and that's starting the VNC session before starting a XFCE4 session on the console.

I found this while googling around for a solution: commit b0eec65b Author: Benedikt Meurer benny@xfce.org Date: Thu Dec 11 17:09:25 2003 +0000

Added check to see if another session is already running.

Dog only knows why Benny thought it was a good idea to allow only 1 XFCE4 session running. But for some reason or another an XFCE4 session running inside VNC is not detected.

Can someone PLEASE have a look at this, or point me to a practical workaround. Fooling around with xfwm4 and xfce4-panel in my .vnc/xstartup file didn't work. xfce4-panel also complains about 'There is already a running instance'.

For me this is a real showstopper for rolling out XFCE4 as the default desktop in our department.

nar..@..il.com said:

(In reply to comment 2)

PS: This bug is also present in XFCE4 4.8 (on Debian Wheezy)

Jérôme Guelfucci closed a related bug:

*** Bug 9918 has been marked as a duplicate of this bug. ***

Jérôme Guelfucci closed a related bug:

*** Bug 9916 has been marked as a duplicate of this bug. ***

Alexis Huxley said:

For those interested, you can see the code that was introduced at http://git.xfce.org/xfce/xfce4-session/tree/xfce4-session/manager.c?id=b0eec65b45fe4417351ca86f85095232df6d2f95.

In addition, I found a nice workaround, which was to strip the enviromnent in ~/.vnc/xstartup before calling xfce4-session. The code in this the above-mentioned change suggested it would be enough to strip SESSION_MANAGER, but this did not prove to be enough, so I stripped everything apart from what I knew I needed. This gave me the following xstartup script, which worked for me:

guest@mandala:~$ cat ~/.vnc/xstartup #!/bin/bash

env -i /bin/sh -c "export PATH=$PATH; export XAUTHORITY=$XAUTHORITY; export DISPLAY=$DISPLAY; export HOME=$HOME; export LOGNAME=$LOGNAME; export USER=$USER; /usr/bin/xfce4-session" guest@mandala:~$

I hope that helps somebody!

Alexis Huxley said:

Minor refinements to workaround script at http://dione.no-ip.org/wordpress/computing/configuring-desktop-environment/

Jon Niehof said:

Following up on Alexis' workaround, it is sufficient to undefine SESSION_MANAGER and DBUS_SESSION_BUS_ADDRESS. This does not need to be done in xstartup, but can be done when starting the vnc session: env -u SESSION_MANAGER -u DBUS_SESSION_BUS_ADDRESS vncserver which leaves xsession alone. One could also edit the vncserver script and fandango on %ENV before the system call, which might be easier than editing every user's .xsession.

Ilya Basin said:

I start Xvnc using the lightdm feature as described here: https://wiki.archlinux.org/index.php/LightDM#VNC_Server I don't use the vncserver wrapper. The environment is already clean: only PATH is set.

It is to show the greeter, I guess, and let the user type the password in the greeter's dialog.

Therefore, I don't see a way to prevent the greeter from setting SESSION_MANAGER and DBUS_SESSION_BUS_ADDRESS

Ilya Basin said:

My workaround is to unset DBUS_SESSION_BUS_ADDRESS at the beginning of /etc/lightdm/Xsession, however, the unneeded dbus-daemon started by its parent remains

mentioned in issue #70 (closed)

added 5. Remote Desktop / VNC label

I found I have to unset XDG_RUNTIME_DIR besides SESSION_MANAGER and DBUS_SESSION_BUS_ADDRESS to make a VNC session successfully start.

Here's my ~/.vnc/xstartup:

#!/bin/sh

unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
unset XDG_RUNTIME_DIR

exec /etc/X11/Xvnc-session

mentioned in issue #193 (closed)

I was unable to start multiple XFCE sessions with NX on EL9. My solution was to start the sessions like this:

dbus-run-session startxfce4

Just in case someone hits the same issue. Regards, Simon

Running xfce4 under vnc xfce4-session report "Another session manager is already running"

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