Cannot Start The Driver Service On Http Localhost Selenium Firefox C Here

options = Options() options.binary_location = r'C:\Program Files\Mozilla Firefox\firefox.exe'

Before we fix it, we must understand it.

Selenium doesn't talk to the Firefox browser directly. It acts as a middleman. Your C# code sends a command to a separate executable called geckodriver.exe. This executable acts as a server, listening for commands on a specific port (usually on localhost).

When you see "Cannot start the driver service," it implies one of three things:

Let's tackle these one by one.

The most reliable way to avoid the "cannot start driver service" error is to let a manager handle binaries.

Python with webdriver-manager:

from selenium import webdriver
from selenium.webdriver.firefox.service import Service
from webdriver_manager.firefox import GeckoDriverManager
service = Service(GeckoDriverManager().install())
driver = webdriver.Firefox(service=service)
driver.get("https://www.selenium.dev")
print(driver.title)
driver.quit()

Benefits:

The “cannot start the driver service on http://localhost” error almost always comes down to:

Fix those, and your Firefox automation will run smoothly.

Did this help? Have another strange Selenium error? Let me know in the comments! options = Options() options

driver = webdriver.Firefox(options=options)

pip install --upgrade selenium

Then download the latest geckodriver and install latest Firefox.

Modern Selenium (4.x+) – Python:

from selenium import webdriver
from selenium.webdriver.firefox.service import Service