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 webdriverfrom selenium.webdriver.firefox.options import Optionsoptions = Options()options.headless = Truedriver = 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

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