 <p><sup>Disclaimer: I'm using Selenium's .NET bindings, not Java. I don't think that will make a difference in this case.</sup></p> <p><a href="https://duckduckgo.com/l/?kh=-1&amp;uddg=https%3A%2F%2Fcode.google.com%2Fp%2Fselenium%2Fissues%2Fdetail%3Fid%3D8399" rel="nofollow">Selenium 2.44 had an issue with Firefox <strong>36</strong></a>, but this was resolved in Selenium 2.45. It's possible that Firefox versions between 29 and 35 might be incompatible with Selenium 2.45, although this is just a guess on my part.</p> <hr> <p>I had an issue with Seleinum 2.45 driving Firefox version <strong>38</strong>: when instantiating the Firefox driver with no profile, an instance of Firefox would load and immediately crash to desktop; subsequently another instance would load as normal.</p> <p>I found that the issue didn't occur when instantiating the Selenium Firefox driver from an existing profile, so my workaround was to create a blank profile, launch Selenium's Firefox driver using a <em>temporary copy</em> of that profile; then at the conclusion of the test, delete the temporary copy.</p> <p>Try <a href="http://docs.seleniumhq.org/docs/03_webdriver.jsp#firefox-driver" rel="nofollow">launching the Firefox driver with an existing profile</a>.</p>