WebDriverException: Message: The browser appears to have exited before we could connect error with GeckoDriver Selenium and Python

Question

There are about 100 posts about the same issue but none of them seem to work for me, hence asking again. I\'m trying to launch a Firefox browser using Python and Selenium an

Answer 1

The issue for me was the mis-match version between python and gekodriver . once all the involved party were 64 bit it worked like a charm

Answer 2

Make sure (especially on Windows (Win 10)) that your browser and controller (python/C/java/perl/etc) is all either x64 or win32, Microsoft will not thunk between them anymore.

So, if your trying to control a 64 bit browser (what will be downloaded by default from firefox) from a x32 bit python, it will exit before you can connect.. go and install a win32 version of firefox for the magic to happen

Answer 3

After trying almost all of the answers on different forums, a simple self trial resolved the problem and i.e. you need to have python, firefox browser and geckodriver in either 62 bit or 32 bit. Mismatch in this caused the problem in my case.

After ensuring that you are using the same bit version for all the 3 components, just use following lines to run firefox:

ffPath = "C:\\Drivers\\geckodriver.exe"
os.environ["webdriver.firefox.driver"] = ffPath
driver = webdriver.Firefox(executable_path=ffPath)
driver.get(url)

Answer 4

This error message...

WebDriverException: Message: The browser appears to have exited before we could connect. 
If you specified a log_file in the FirefoxBinary constructor, check it for details.

...implies that the GeckoDriver was unable to initiate/spawn a new WebBrowser i.e. Firefox Browser session.

You need to take care of a couple of things as follows:

• To set the FirefoxBinary you need to use the FirefoxOptions() and instead of passing the absolute path of geckodriver binary, you have to pass the absolute path of the desired firefox binary.
• As you are using GeckoDriver v0.21.0 you have to mandatorily use marionette so either keep it unchanged (by default true) or set marionette to true.

• Your own code with incorporating the minor changes will be:

  from selenium import webdriver
  from selenium.webdriver.firefox.options import Options
  from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
  
  binary = r'C:\Program Files\Mozilla Firefox\firefox.exe'
  options = Options()
  options.set_headless(headless=True)
  options.binary = binary
  cap = DesiredCapabilities().FIREFOX
  cap["marionette"] = True #optional
  driver = webdriver.Firefox(firefox_options=options, capabilities=cap, executable_path="C:\\Utility\\BrowserDrivers\\geckodriver.exe")
  driver.get("http://google.com/")
  print ("Headless Firefox Initialized")
  driver.quit()
  

• Console Output:

  Headless Firefox Initialized
  

• Here you can find a detailed discussion on Unable to find a matching set of capabilities with selenium 3.4.3, firefox 54.0 and gecko driver 0.17

Answer 5

binary = r'C:\Program Files\Mozilla Firefox\firefox.exe'
options = Options()
options.binary = binary
browser = webdriver.Firefox(firefox_options=options, executable_path=r"C:\Drivers\geckodriver.exe")