Firefox via GeckoDriver throws exception on .Quit() in Selenium 3.0.1

Question

Context: Firefox 50.0.2 64bit, C#, Visual Studio 2015, Windows Server 2012 R2, Azure, ClearScript.V8.5.4.7, Selenium.Mozilla.Firefox.Webdriver.0.6.0.1, Selenium.WebDriver.GeckoDriver.Win64.0.11.1

I'm using ClearScript to wrap the Selenium objects for use in JavaScript, viz

    static JScriptEngine JSengine = null;
    ...
    JSengine = new JScriptEngine(WindowsScriptEngineFlags.EnableDebugging | WindowsScriptEngineFlags.EnableJITDebugging);
    ...
    JSengine.AddHostType("CSFirefoxDriver", typeof(FirefoxDriver));
    JSengine.AddHostType("CSFirefoxOptions", typeof(FirefoxOptions));
    JSengine.AddHostType("CSFirefoxDriverService", typeof(FirefoxDriverService));

I instantiate Firefox using the following JS

var driverService = CSFirefoxDriverService.CreateDefaultService();
driverService.FirefoxBinaryPath = "C:\\Program Files\\Mozilla Firefox\\firefox.exe";
driverService.HideCommandPromptWindow = true;
driverService.SuppressInitialDiagnosticInformation = true;
var options = new CSFirefoxOptions();
driver = new CSFirefoxDriver(driverService, options, CSTimeSpan.FromSeconds(30));

The matching Quit/Dispose code is

try {
  driver.Quit();
} catch (E) {
  T.Error().Send("driver.Quit() failed.");
}

try {
  driver.Dispose();
} catch (E) {
  T.Error().Send("driver.Dispose() failed.");
}

(T is a logging object)

When the .Quit() method call is executed, I get the following dialog.

If I comment out the the .Quit() then I get the same on the .Dispose().

Other forums have suggested turning off hardware acceleration in Firefox's preferences. This has not made any difference at all.

There is also an issue on the geckodriver forum about this claiming a fix of some sort. It's certainly not fixed now.

Windows Event Log isn't particularly helpful here, viz

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
    <System>
        <Provider Name="Application Popup" Guid="{47BFA2B7-BD54-4FAC-B70B-29021084CA8F}" /> 
        <EventID>26</EventID> 
        <Version>0</Version> 
        <Level>4</Level> 
        <Task>0</Task> 
        <Opcode>0</Opcode> 
        <Keywords>0x8000000000000000</Keywords> 
        <TimeCreated SystemTime="2016-12-13T03:16:28.936810900Z" /> 
        <EventRecordID>1227958</EventRecordID> 
        <Correlation /> 
        <Execution ProcessID="5856" ThreadID="11580" /> 
        <Channel>System</Channel> 
        <Computer>VM1-SQLWEB-W12</Computer> 
        <Security UserID="S-1-5-18" /> 
    </System>
    <EventData>
        <Data Name="Caption">firefox.exe - Application Error</Data> 
        <Data Name="Message">The exception Breakpoint A breakpoint has been reached. (0x80000003) occurred in the application at location 0x880f00ef. Click on OK to terminate the program Click on CANCEL to debug the program</Data> 
    </EventData>
</Event>

Where do I go from here? I can fall back to PhantomJS until a fix is found.

Answer 1

I had the same problem, I found that someone posted it here. For now you can downgrade to Firefox 48.0.2 until it is fixed.