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self-installer notes Windows install details EXPGUI home

Installating and Updating
EXPGUI (& GSAS) on Windows

Please note that EXPGUI is always under development and gets less testing by the author in Windows than in other platforms. Please report problems, including improvements on these instructions to Brian Toby. Otherwise, Windows-specific issues are unlikely to be addressed or repaired.

Installing GSAS and EXPGUI in Windows

Most users who install GSAS (General Structure Analysis System) and EXPGUI, will do so by downloading a single file that installs the GSAS programs, the Tcl/Tk package (with some extensions), the EXPGUI scripts, as well as makes registry entries & defines shortcuts. This will be described in brief in the next section of this page. It is also possible to download and install GSAS, Tcl/Tk & EXPGUI from separate distributions; please see the Windows install details web page for more details.

More information about EXPGUI, including information on how it can be customized, can be found on web pages expgui.html and expgui_cfg.html. These files are also found in the ...\gsas\expgui\doc directory after EXPGUI is installed.

Using the GSAS and EXPGUI self-installer for Windows

You can download a single file that installs GSAS and EXPGUI, as well as the Tcl/Tk package, needed by EXPGUI. This self-installing file uncompresses itself, copies the required files to a selected directory and creates the appropriate registry entries needed to run the programs. A separate web page provides details a detailed description on this self-installer (gsas+expgui.exe). Here are the steps in brief:

  1. Download
    (Mirrors: select file gsas+expgui.exe from UK, Canada or Australia.)

  2. Run the gsas+expgui.exe file

  3. Page through the installation screens & select install options

  4. Wait while the files are installed.

  5. Delete the gsas+expgui.exe file (optional)

For more details on the sequence of operations and the installation options refer to the detailed Windows self-installer instructions web page.

Updating to a new GSAS release

It is quite common that Bob Von Dreele will release an update to the GSAS programs more frequently than the combination gsas+expgui.exe package can be updated. It is possible to update a previous version of the GSAS software. First, make a note where you have installed the GSAS/EXPGUI software. The default is C:\GSAS, but you can check by looking at the properties for the PC-GSAS or EXPGUI icon. Second, note the GSAS package date, by running a GSAS program, such as EXPEDT or SPACEGRP and noting the date where it says "Distributed on ..." Then download the latest GSAS release from CCP14:

When you run the downloaded file, you will be asked where the GSAS software should be installed (with a default of C:\GSAS). Make sure to use the same location as before.

Finally, check that GSAS has indeed been updated by again running a GSAS program, such as EXPEDT or SPACEGRP and noting the date where it says "Distributed on ..."

Updating to a new EXPGUI release

It is also common that new features will be added to EXPGUI or bug fixes will be made without an update to the combination gsas+expgui.exe package. The absolute latest release (which may not have gotten a lot of testing) is distributed as On the newest versions of Windows, support for .zip files is built in, but for older versions, you will need an unzip program, such as WinZip or pkZip.

To update EXPGUI, first, make a note where you have installed the GSAS/EXPGUI software. The default is C:\GSAS\EXPGUI, but you can check by looking at the properties for the PC-GSAS or EXPGUI icon. Second, note the EXPGUI package date, by using the Help/About menu command in EXPGUI. You then want to download this file: is distributed as
(Mirrors: select file from UK, Canada or Australia.)

and unpack it to subdirectory ...\gsas\expgui\. Depending how you work with the zip directory, you may want to copy the files in the .zip archive into the existing gsas\expgui directory or rename the original expgui in gsas and then drag the new expgui directory into the gsas folder. Finally, you can check if the EXPGUI program has been updated, by restarting it and again using the Help/About menu option.

Problems & Questions

  1. Where can the software be installed?
      Do not install the software on a directory containing a space (for example, C:\Program files\GSAS). This will cause some of the shortcuts to break.

      On Windows-95/-98 or -ME, if you install in a location other than C:\GSAS, you will need to define the GSAS environment variable in your AUTOEXEC.BAT file by adding a line like this:

              SET GSAS=G:\MySoftware\GSAS
  2. How do I increase the Environment variable space
      This is only needed on -95/-98 or -ME. To add more environment space in Win95/98, add the following line to the CONFIG.SYS file in the root directory
              SHELL=C:\WINDOWS\COMMAND.COM /P /E:4096 
      Also add the following line to the SYSTEM.INI file (in c:\windows) under the heading [NonWindowsApp]
      (thanks to Louis Farrugia [] for this).
  3. What versions of Windows can I use?
      As far as I am aware, EXPGUI will run under all releases of Windows from -95/-98/-ME/-NT/-2000 through -XP, but it is not tested here on most of those platforms. I depend on feedback from users to tell me of OS conflicts, but none have been reported.
  4. EXPGUI seems pretty slow, or is it my imagination?
      Well, actually the problem is Windows. EXPGUI is pretty zippy in LINUX, but some operations (reading a histogram in liveplot for example) can take 3-5 times longer in Windows than in UNIX on the exact same hardware. By all means, take this up with the folks in Redmond, WA.
  5. When I run one of the GSAS graphics programs (POWPLOT, RAWPLOT,...) the program starts, and I can answer questions, but when it comes to the part of the program that should display a plot, I get no plot (and possibly the DOS window disappears without a trace.)
      There are two problems I know of that can cause graphics errors: One is that the graphics package (PGPLOT) cannot find the PGPLOT_FONT environment variable (that points to file GRFONT.DAT). EXPGUI does this for you and warns if it can't find this file, so the likely reason is that you are out of environment space (see 2, above).

      The other appears to be a graphics mode problem. Not all modes work on all machines. Try mode A. If you still have problems, see if it is an EXPGUI problem: Try using a plotting program (RAWPLOT is a good choice) from PC-GSAS or GSAS.BAT. If the plotting program does not work there either, first check PGPLOT_FONT is defined (by opening a DOS box and type SET, also see question 2, above.) If the plotting program runs in PC-GSAS or GSAS.BAT but not EXPGUI, you have a real EXPGUI bug and should bug me.

  6. Can GSAS and EXPGUI be located on a shared network drive?
      Yes. With earlier versions of GSAS path had to be mapped to a "logical drive." (e.g. F:). In the current versions of GSAS, this does not seem to be needed, but EXPGUI will warn you, if you try to do this, since I am not certain that this works.

      I do not know if GSAS will work properly with experiment and data files on a networked drive without mapping the path to a "logical drive." There are some definite problems in GSAS where directory and file names contain spaces so EXPGUI generates warning messages if you do this.


GSAS is written by Allen C. Larson and Robert B. Von Dreele, MS-H805, Los Alamos National Laboratory, Los Alamos, NM 87545. Problems, questions or kudos concerning GSAS should be sent to Robert B. Von Dreele at

EXPGUI is written by Brian H. Toby of the NIST Center for Neutron Research, Brian.Toby@ANL.GOV with help from Jonathan Wasserman.

GSAS is Copyright, 1984-1997, The Regents of the University of California. The GSAS software was produced under a U.S. Government contract (W-7405-ENG-36) by the Los Alamos National Laboratory, which is operated by the University of California for the U.S. Department of Energy. The U.S. Government is licensed to use, reproduce, and distribute this software. Permission is granted to the public to copy and use this software without charge, provided that this notice and any statement of authorship are reproduced on all copies. Neither the Government nor the University makes any warranty, express or implied, or assumes any liability or responsibility for the use of this software.

EXPGUI is not subject to copyright. Have fun with it.

Neither the U.S. Government nor any author makes any warranty, expressed or implied, or assumes any liability or responsibility for the use of this information or the software described here. Brand names cited here are used for identification purposes and do not consitute an endorsement by NIST.

self-installer notes Windows install details EXPGUI home

Last modified 25-January-2007 by website owner: NCNR (attn: Craig Brown)
$Revision: 1.29 $ $Date: 2007/01/25 22:56:52 $