Some users have had issues installing OpenMDAO under certain circumstances. In this section, we’ll address some of the most common installation pitfalls. We’ll also discuss what you can do to receive assistance when faced with an installation problem or error message that you don’t understand.


The OpenMDAO Open Source Question and Answer (OSQA) Forum ( is the first place that you should go to find an answer to your question. Search this forum before asking a question or commenting on existing questions (e.g., “I have this problem, too!”). If a question is asked just once, it’s probably unique. Remember to follow forum etiquette – upvote and downvote answers and comments, and formally accept an answer when you are satisfied.

Inspecting Your Python Environment


You may have trouble installing OpenMDAO or experience a test failure, and the reasons why might not be readily apparent. If this happens, it may help to examine the environment where you are attempting the installation. OpenMDAO provides a specific environment-dumping script for extracting this information.

If the installation was successful, then from a prompt in an activated environment, you can simply type:


A full output of the machine’s environment will be printed to the screen.

If the installation was not successful, then you won’t have the script yet, but you can download the script from the Miscellaneous Downloads section at Once the script is downloaded, to manually run it, type:


This should produce the same results as running the envdump console script. Sometimes, examining the output of the environment will expose obvious path problems that can expedite the troubleshooting process.

Capturing Envdump, Installation Output, or Test Output

At times, a problem will not have an obvious fix, and you might want to get help from the OpenMDAO developers. The first step, as discussed above, should be to post your question in the OpenMDAO forum. Posting in the forum makes sure that the answers are archived for others who have the same problem. If the problem can’t be solved easily though, the OpenMDAO developers might request more detailed information from you. In these cases you will need to capture the output of an attempted installation, a test run, or an envdump (or more than one of these events) and send the full report(s) to the OpenMDAO development team for inspection.

When directing standard output (I/O stream 1) and standard error (I/O stream 2) into the same file, try:

command 1> filename 2>&1

(Where command is something like python or openmdao test, and where filename is something like my_envdump.txt or my_testoutput.out.)

Once the outputs have been captured into properly named files, please email the files to the OpenMDAO development team using the email

Common Install Problems

  • In general, OpenMDAO supports the specified versions of Python found at At this time we do not officially support alternate Python builds, such as Enthought, ActiveState Python or Python(x,y), although some may work with OpenMDAO.
  • OpenMDAO does not support Python 3.x, nor does it support Python versions below 2.6.5. Having the incorrect Python installation in the PATH and/or not having the OpenMDAO-approved Python version in the PATH will only lead to problems.
  • Versions of numpy and scipy that are incompatible with the Python version installed often cause problems, such as failing tests. Several users have had problems when they already had an existing Python installation and existing versions of numpy or scipy installed. The users updated Python – but not the numpy or scipy – to the corresponding versions. In such cases strange errors can occur that are tough to diagnose.
  • Remember that when you install new Python versions or compilers and then add them to the PATH, it’s necessary to restart the system shell to see the change. Put more simply, you need to close the command window (a.k.a. terminal window) and open a new one so the changes to the PATH will take effect.
  • If you try to run things without activating the virtual environment, it will seem as though programs have not been installed. You need to activate your environment every time you open a new shell.
  • If you have multiple versions of Python installed on your machine, then make sure that the version that’s being run when you type python is an OpenMDAO-compatible version. Otherwise, you need to specify the Python version in the command line, e.g., python2.7
  • If you forget to deactivate the virtual environment when finished, and the virtualenv gets changed, you’ll encounter problems. You’ll have to deactivate the virtualenv, change it, rebuild, and then reactivate it.

Windows Specific

  • Usernames with spaces have been known to cause various problems in our tests for distributed simulations.
  • When you install Python on Windows, the PATH environment variable won’t be updated to include the installation directory. You’ll need to update it manually, and if you don’t, problems may result.

Mac OS X Specific

  • Installing the proper version of XCode and the proper combination of C and Fortran compilers is the most challenging thing to get OpenMDAO running with Leopard, Snow Leopard, and Lion. See the System Requirements for more details on getting this correct.
  • When the system is trying to use g77 instead of gfortran: If you have g77 installed and you’re seeing errors like ld: library not found for -lcc_dynamic, you can just rename g77 to _g77 or something else to avoid g77 being found. Then gfortran will be used, and things will work properly again.

Linux Specific

  • If you do not install or test in bash, failures will occur.
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