X11 server – OS X issue

If you have ever got this message from “ssh -x user@host”

“An error occured while starting the X11 server: Cannot establish any listening sockets – Make sure an X server isn’t already running.”

make sure to check whether you have /tmp/.X11-unix directory. If you do so, simply remove it

shell> rm -rf /tmp/.X11-unix

X11 server fails to remove this file from time to time.

*** Update ***

Step by step instructions (as one of the commenters made a request for it):

1. Open Terminal

Applications -> Utilities -> Terminal

2. Go to /tmp directory (type into terminal command specified below)

cd /tmp

3. Remove .X11-unix directory (type into terminal command specified below)

rm -rf .X11-unix

Comments (11)

anonymousNovember 27th, 2012 at 2:59 am

Thanks, I had been struggling with that.

anonymousFebruary 10th, 2013 at 7:58 am

HOW step by step please
where do I look for this

anonymousFebruary 11th, 2013 at 3:25 pm

Hi all,

So I find an .X11-lock file — but removing it doesn’t stop an infinite loop behavior that has the X11 window continuing to reappear — its a bit of a nightmare actually.

anonymousFebruary 11th, 2013 at 6:33 pm

This is strange.

Maybe you can try upgrading to XQuartz. In fact, XQuartz is the only option for the Mountain Lion when it comes to X11 applications.


anonymousFebruary 11th, 2013 at 6:34 pm

One more suggestion. If you run into infinite loop, have you tried to kill X11 by going to:

Finder -> Apple -> Force Quit … -> X11

and killing X11 prior to removing .X11-lock files?

anonymousMay 21st, 2013 at 10:40 pm

After trying everything on this page and more, I was still having trouble. I had messages in the Console about not being able to create /tmp/.ICE-unix, /tmp/.X11-unix and /tmp/.font-unix. I finally got this fixed by hacking the /opt/X11/lib/X11/xinit/privileged_startx.d/10-tmpdirs script. There is a comment in there that reads, “# Our usage of mktemp fails with GNU, so prefer /usr/bin to hopefully get BSD mktemp”. I went to the terminal and ran /usr/bin/mktemp –help, and found that this computer has the GNU version, so we know it’s not going to work. What I did was to change the script where it has:

if ${MKTEMP} -d ${dir} >& /dev/null ; then


if mkdir ${dir} >& /dev/null; then

and now it creates the directory successfully.

anonymousJune 4th, 2013 at 3:16 pm

Matthew Bishop’s method solved my problem

anonymousMay 8th, 2014 at 9:00 pm

I had the same issue where X11/XQuartz would not start because /tmp/.{X11,ICE,font}-unix were not created properly as an unprivileged user (me). They were removed (along with everything else) from /tmp on startup. Matthew Bishop’s patch above didn’t work for me.
I resolved the issue by putting this line at the bottom of my /etc/rc.local file (runs as root on bootup):


thus the needed dirs are created at bootup by root and all is well.

anonymousApril 1st, 2015 at 6:26 pm

Thanks Mr Bishop. Those 3 tmp directories on my system were deleted somehow. I ran the following:
sudo /opt/X11/lib/X11/xinit/privileged_startx.d/10-tmpdirs

and it created the /tmp/.ICE-unix, /tmp/.X11-unix and /tmp/.font-unix for me. Afterwards, XQuartz came up normally.

anonymousMay 19th, 2015 at 1:47 pm

Oh god thank you so much Matthew Bishop. My problem is solved

anonymousMay 19th, 2015 at 1:52 pm

I spoke too fast : X11 doesn’t crash anymore but inkscape doesn’t work