As of Firefox version 47.0 (which came out a little while a go), a new driver must be used (created by mozilla instead of selenium) to connect to Firefox, because of a bug introduces in this version. As of Firefox version 48.0 the old driver will be deprecated completely and only Marionette can be used so it is better to switch now. See: Marionette Webdriver for Firefox

Download the driver (in OSX just use brew install geckodriver), rename the executable to wires.exe on windows, or wires on *nix systems, and make sure the executable is present in your system path, then use this driver in your program instead of the old driver by using the following:

When using a local webdriver:

Python:

firefox_capabilities = DesiredCapabilities.FIREFOXfirefox_capabilities['marionette'] = Truedriver = webdriver.Firefox(capabilities=firefox_capabilities)

Ruby:

driver = Selenium::WebDriver.for :firefox, marionette: true

Javascript:

var capabilities = Capabilities.firefox();capabilities.set('marionette', true);var driver = new webdriver.Builder().withCapabilities(capabilities).build();

Java:

DesiredCapabilities capabilities = DesiredCapabilities.firefox();capabilities.setCapability("marionette", true);Webdriver driver = new FirefoxDriver(capabilities);

C#:

var driver = new FirefoxDriver(new FirefoxOptions());

When using selenium grid:

When using a selenium grid the driver should be present in the path for all machines in your grid.

Python:

firefox_capabilities = DesiredCapabilities.FIREFOXfirefox_capabilities['marionette'] = Truedriver = webdriver.Firefox(capabilities=firefox_capabilities)

Ruby:

caps = Selenium::WebDriver::Remote::Capabilities.firefox marionette: truedriver = Selenium::WebDriver.for :firefox, desired_capabilities: caps

Java:

DesiredCapabilities capabilities = DesiredCapabilities.firefox();// Set Marionette on so the Grid will use this instead of normal FirefoxDrivercapabilities.setCapability("marionette", true);WebDriver driver = new RemoteWebDriver(capabilities); 

C#:

DesiredCapabilities capabilities = DesiredCapabilities.Firefox();// Set Marionette on so the Grid will use this instead of normal FirefoxDrivercapabilities.SetCapability("marionette", true);var driver = new RemoteWebDriver(capabilities); 

FIXED:Solution at this time is to downgrade Firefox!run this command to get a list of available Firefox versions.

apt-cache show firefox | grep Version

My Result:

Version: 47.0+build3-0ubuntu0.16.04.1Version: 45.0.2+build1-0ubuntu1

Install:

sudo apt-get install firefox=45.0.2+build1-0ubuntu1

To keep this version and disallow updates:

sudo apt-mark hold firefox

If you want to unhold firefox version and allow updates:

sudo apt-mark unhold firefoxsudo apt-get upgrade

Solution : Upgrade Firefox to 47.0.1 and Selenium to 2.53.1.

This combination worked for me.

For more details refer to https://stackoverflow.com/a/37728659/6469532