I just installed (64 bit) Firefox 18 browser on my Linux CentOS 6.4 server (64 bit). I SSH into the server from my Mac OSX Snow Leopard from X11 application using # ssh -Y mydomain.com. Now that the Mac is connected to the server, I run firefox on the server by typing in the X11 terminal on my Mac, # firefox&.

While firefox is forwarded to my Mac, and appears to run OK, the following errors are reported in the X11 terminal it was opened with:

Xlib:  extension "RANDR" missing on display "localhost:10.0".
(firefox:14774): GLib-GIO-WARNING **: Failed to execute child process "update-mime-database" (No such file or directory)
[the last error repeats 4 more times]

I installed firefox in the server's /opt directory as root user. I simply extracted Mozilla's .tar.bz2 file, and did no other setup other than ensure X11 forwarding works (ssh_config file on server). The browser opened to Mozilla's default webpage.

I was not able to find anything applicable to this after a google search. Wondering if anyone knows what these errors mean, what effect they will have, and finally how to remove them.

  • Can you please clarify the question to explain better how OS X is involved in the problem you are facing?
    – nohillside
    Commented Jul 30, 2013 at 16:14
  • The question was originally posted on ServerFault, which was downvoted and closed and referred to post here because of X11 terminal interfacing with a Mac OS. If it's not server related (e.g. ServerFault) and not Mac related (e.g. here), perhaps you can recommend where I might post next. The question is how to eliminate the error messages I observe when SSH into server from Mac OS.
    – user54208
    Commented Jul 30, 2013 at 16:43
  • I don't say it doesn't belong here. But as it is written it's quite difficult to understand what you are doing, what part happens on Linux and OS X and which error/warning get's thrown when. Can you try to improve the question to make this more easy to understand and request a reopen?
    – nohillside
    Commented Jul 30, 2013 at 17:47
  • Modified posting above to make clearer.
    – user54208
    Commented Jul 30, 2013 at 19:05
  • 1
    It is Mac related because the firefox process running on Linux (which in X11 terminology is the x11 client) is trying to use an X11 extension (RANDR) which is not present in the version of quartz (which in X11 terminology is the "X11 server") that is running on the Mac. As I state in my answer below, later versions have that extension.(edited below to show that) And to be clear, that is a warning, not an error. That extension's presence is not mandatory for the x11 client process. That is one artifact of the flexibility of X11: it will sometimes warn you about stuff that is not fatal.
    – Tim B
    Commented Jul 31, 2013 at 14:18

1 Answer 1


For the first warning on RANDR, try installing a newer version of xquartz

Searching there just now, it looks like randr was added. I can confirm that on my system which is running xquartz 2.7.4 on OS-X 10.7.5:

$ xrandr -v
xrandr program version       1.3.5
Server reports RandR version 1.3
$ sw_vers | grep 'ProductVersion:' | grep -o '[0-9]*\.[0-9]*\.[0-9]*'

enter image description here

For the last warning, does "update-mime-database" exist on the system in the user's $PATH?

  • Thanks @Tim B, installing and running xquartz on the Mac did remove the RANDR warning observed on the server. When I SSH into server as user and type echo $PATH I do not see update-mime-database in it. Do you know what this does (I wonder if it's important)? As an aside, any idea why X11 forwarding of Firefox results in Firefox being sooooo very slow?
    – user54208
    Commented Jul 31, 2013 at 16:07
  • As root on server, I searched find / -iname update-mime-database and it returned nothing.
    – user54208
    Commented Jul 31, 2013 at 16:30
  • 1
    So you don't have that package installed. You can install it or ignore the warning. (it is common to redirect stderr to /dev/null to ignore x11 client warnings like this)
    – Tim B
    Commented Aug 1, 2013 at 12:21

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