# Installing OpenMx

### What computers run OpenMx?

You can run recent versions of OpenMx on computers using Windows 7 or later, MacOS 10.6 or later, and most varieties of Linux/GNU (32- and 64- bit).

### What do I need to do first?

In order to install the most recent version of OpenMx, you will need R version 3.1.0 or higher. Version 1.x of the package will work with R version 2.9.x or higher. Unfortunately there is a bug in R version 2.10.0 that prevents the use of our automatic installer.

If you need to download R, it can be found at CRAN.

IMPORTANT for legacy-version users: if you are running R 3.1 AND your version of OpenMx is 1.3.2-xxxx or 1.4-xxxx, where xxxx is less than 3475, please re-install OpenMx and re-run any analyses you did with it in R 3.1. Version 3.1 of R introduced a small change in R's interface with compiled code that could potentially cause certain OpenMx scripts to compute numerically incorrect solutions. This problem was fixed as of revision number 3475.

### How do I install OpenMx?

Next, open up an R session and copy the following line into the R command line and press return.

source('http://openmx.psyc.virginia.edu/getOpenMx.R')

If you don't have a default CRAN repository, you will be prompted to pick one. Just pick a repository near you and press the OK button. If you do have a default CRAN repository, you won't see that panel.

Important additional consideration for OS X users with R version 3.1
The installation procedure is slightly more complicated for Mac users with OS-X Mavericks who want to run R 3.1.0. Due to a peculiarity of the Mavericks-only version of R 3.1.0, a minor work-around is necessary. First, you must install R as R-3.1.0-snowleopard.pkg and update your installed packages. Then within R, you can install OpenMx by copying the command source('http://openmx.psyc.virginia.edu/getOpenMx.R') as usual.

Now you should be ready to take a look at the Tutorial User Guide.

Take a look at third party software that extends the functionality of OpenMx.

If you are interested in building OpenMx from source, take a look at the OpenMx Compilation How-To Guide.