Cannot Start The Driver Service On Http Localhost Selenium Firefox C 'link' Jun 2026

temporarily (Chrome or Edge) to determine if the issue is Firefox-specific or stems from a broader environment problem

The error message WebDriverException: Cannot start the driver service on http://localhost:... is a common frustration for C# developers using Selenium with Firefox. It means the GeckoDriverService tried to launch the Firefox driver executable on your machine, but the communication channel between your C# code and the driver failed to establish.

The error "Cannot start the driver service" is sometimes a polite way of saying "The OS blocked the executable." temporarily (Chrome or Edge) to determine if the

Ensure your firewall isn't blocking geckodriver.exe from communicating over localhost. 5. Clean Temporary Files

public class FirefoxDriverFixture : IDisposable The error "Cannot start the driver service" is

Knowing these details can help us identify a more specific solution.

Ensure traffic targeting 127.0.0.1 and localhost is completely unblocked. 3. VPN and DNS Loopback Issues Ensure traffic targeting 127

// Define the service using that path FirefoxDriverService service = FirefoxDriverService.CreateDefaultService(driverPath);

When developing browser automation scripts using the in C# , hitting a roadblock early in the execution phase can be incredibly frustrating. One of the most prevalent and disruptive exceptions you might encounter is: