org.openqa.selenium.SessionNotCreatedException: Unable to find a matching set of capabilities while initiating Firefox v37 through Selenium v3.11.0

To keep things simple, as you are using Selenium Client v3.11.0 and Firefox v37 you need to download the latest GeckoDriver from mozilla/geckodriver and save it any where within your system. Next within the System.setProperty() line pass the Key webdriver.gecko.driver along with the Value as the absolute path of the GeckoDriver and finally through DesiredCapabilities class set the capability marionatte to false and merge into an instance of FirefoxOptions instance to initiate the Firefox browser as follows :

System.setProperty("webdriver.gecko.driver", "C:/path/to/geckodriver.exe");
DesiredCapabilities dc = new DesiredCapabilities();
dc.setCapability("marionatte", false);
FirefoxOptions opt = new FirefoxOptions();
FirefoxDriver driver =  new FirefoxDriver(opt);
System.out.println("Application opened");
System.out.println("Page Title is : "+driver.getTitle());


As per your comment update you are using GeckoDriver v0.20.1.

But if you look back at the Release Notes of GeckoDriver v0.18.0 it clearly mentions :

geckodriver now recommends Firefox 53 and greater

So using GeckoDriver v0.18.0 and above you have to mandatory use Firefox 53 and greater. To get rid of this constraint you can downgrade either to any of these versions :

  • GeckoDriver v0.17.0
  • GeckoDriver v0.16.1