Table of Contents

If you have problems with Cygwin/X then you can try to find a solution on this page. Much more is covered in the FAQ but the sections here will be filled in the next weeks.

If you have found a solution to a problem, feel free to add it to the appropriate section.



cygX11-6.dll not found after installation or upgrade

Reinstall the xorg-x11-bin-dlls package. Make sure not to reinstall any XFree-* packages. Check if /usr/X11R6/bin/cygX11-6.dll does exist. Check if $PATH contains /usr/X11R6/bin.



If your keyboard layout is not configured correctly (eg you only get the us layout) please contact the Cygwin/X mailinglist and send your /tmp/XWin.log or at least the lines similar to these:

(--) winConfigKeyboard - Layout: "00010407" (00010407) 
(--) Using preset keyboard for "German (Germany, IBM)" (10407), type "4"

With this information it is possible to add that entry to the list of known keyboard layouts. If you already know which is the correct XKB layout code for your layout please state it in the mail. This will make things quite easy me.

Cygwin/X Startup

Cygwin/X freezes right after startup

Zone Alarm (esp version 5) was reported to break Cygwin/X. Check the log file. The last line will say something about keyboard layouts. remove Zone Alarm to get rid of this.

make sure /tmp is mounted in binmode

Duplicate invocation error

Most likely you have started XWin twice with startxwin.bat or startx or a similar script. You can't do this. You can only start XWin once. If you want another terminal window (which in fact is just a convenient side effect of running startxwin.bat) you should do this by starting xterm from the cygwin shell or from the startmenu entries.

Multiple Users, Multiple XWin

If you want to start XWin multiple times, you have to assign each of them a unique display number eg XWin :0 $OPTIONS (this is the default) or XWin :1 $OPTIONS.

If you start XWin with different users and get access proplems in /tmp/.X11-unix then disable the unix sockets connection scheme by starting the xserver with XWin -nolisten unix $OPTIONS. The $DISPLAY variable :0.0 will not work anymore but can be replaced with localhost:0.0.

The root window is not shown when starting XWin

This is a small problem with run.exe. If you start XWin with -nodecoration, -multiwindow or -fullscreen the window will come up normally.


X as default pointer in multiwindow mode

To workaround this add the command run xsetroot -cursor''name left''ptr -fg white -bg black to startxwin.bat


Resizing XTerm does not change linewidth in bash

Try starting resize. See mail for details.


Personal Firewalls

Cygwin/X requires properly working TCP/IP even for local connections. It listens on port 6000 + display number (eg. 6002 for display :2.0). If you use the internal clipboard manager or the multiwindow feature it creates network connections even if no other client is connected.

If you are running a personal firewall make sure you set a rule which allows XWin.exe to connect to the port and a rule which allows it to accept connections on the port.

If you are still experiencing problems try disabling the Personal Firewall.

Zone Alarm

There have been reports that programs are experiencing network problems when running Cygwin/X with Zone Alarm installed. This is because cygwin creates a new socket everytime select is called and the Zone Alarm networking stack will then kill connections which are already running on that port.

Remote Usage

SSH X11 Forwarding

Programs report strange errors

See FAQ Entry

Cygwin/X reports AUDIT: client 1 rejected from IP ''remotehost''

By default remote connections are not allowed (security). You can work around this by either of:

  1. add -ac to your Xwin.exe arguments (e.g. in \cygwin\bin\startxwin.bat)
  2. use the xhost program (you may need to run cygwin setup to install it) to allow access.
    1. xhost + to allow all hosts
    2. xhost +yourappserver to allow just clients on yourappserver. If you're using XDMCP then the problem may be wrong DNS resolution. Make sure your windows host has a hostname which is valid from linux too and an IP address which linux can resolve to that hostname.

If you add a line myhost

to /etc/hosts on the XDMCP server containing the IP address and the hostname of your windows host the name resolution should work.

Unix flavours

Keys or mouse buttons not working on AIX, SUN Solaris, HPUX

Disable NumLock. Some programs treat NumLock as a modifier like Control.

A small program which will do this is available here

No keyboard input in Java

Disable NumLock. Same problem as above.

Mouse buttons not working in Motif applications on SUN Solaris

This is a bug in the Motif libraries from SUN. See details. There is a patch available from SUN: :Patch 108940.

-- AlexanderGottwald - 21 Nov 2004