WebDriverException: Message: invalid argument: can't kill an exited process with GeckoDriver, Selenium and Python on RaspberryPi3

If you are running Firefox on a system with no display, make sure you use headless mode.

from selenium import webdriver
from selenium.webdriver.firefox.options import Options

options = Options()
options.headless = True
driver = webdriver.Firefox(options=options)

Also, make sure you have compatible versions of Firefox, Selenium, and Geckodriver: https://firefox-source-docs.mozilla.org/testing/geckodriver/Support.html


Thumb rule

A common cause for Browsers to crash during startup is running WebDriver initiated Browsers as root user (administrator) on Linux. While it is possible to work around this issue by passing --no-sandbox flag when creating your WebDriver session, such a configuration is unsupported and highly discouraged. You need to configure your environment to run Browser as a regular user instead.


This error message...

selenium.common.exceptions.WebDriverException: Message: invalid argument: can't kill an exited process

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

Your main issue is the incompatibility between the version of the binaries you are using as follows:

  • Your GeckoDriver version is 0.22.0.

  • Release Notes of GeckoDriver v0.21.0 (2018-06-15) clearly mentions the following:

  • Firefox 57 (and greater)

  • Selenium 3.11 (and greater)

  • Your Firefox version is 52.9.0.

So there is a clear mismatch between GeckoDriver v0.22.0 and the Firefox Browser v57


Solution

  • Upgrade GeckoDriver to GeckoDriver v0.22.0 level.
  • GeckoDriver is present in the specified location.
  • GeckoDriver is having executable permission for non-root users.
  • Upgrade Firefox version to Firefox v62.0.2 levels.
  • Clean your Project Workspace through your IDE and Rebuild your project with required dependencies only.
  • If your base Web Client version is too old, then uninstall it through Revo Uninstaller and install a recent GA and released version of Web Client.
  • Execute your Selenium Test as a non-root user.

GeckoDriver, Selenium and Firefox Browser compatibility chart

geckodriver_versions


I was on headless mode, using correct versions of everything, and the only way to get out of this error message was not to execute the selenium test as root