Visual Studio 2015 break on unhandled exceptions not working

There's a new window called "Exception Settings" that appears in the lower right pane by default when you begin debugging. It has all of the options you would expect.

You can bring it up with CTRL+ALT+E

This allows you to cherry-pick which exceptions cause a break in the debugger.

The key, though, is that you can also set whether these exceptions always break, or only break when it's an unhandled exception -- but setting this is not very intuitive.

You will need to first check "Enable Just My Code" under Tools > Options > Debugging.

This then allows you to right-click the column header (Break When Thrown) in the new Exceptions Settings window, and add the "Additional Actions" column, which then allows you to set each exception as "Continue when unhandled in user code".

So just right-click an exception or an entire group and disable the "Continue when unhandled in user code" flag. Unfortunately, the "Additional Actions" column will show up empty which is the same as "Break when unhandled in user code".

https://i.stack.imgur.com/ltXUq.png

More on this here:

http://blogs.msdn.com/b/visualstudioalm/archive/2015/02/23/the-new-exception-settings-window-in-visual-studio-2015.aspx

I had the same issue and I managed to solve this by doing this -

Press Ctrl + Alt + e to bring up the Exception Settings window. Tick Common Language Runtime Exceptions.

That's it!

I was inspired this post since I am using a x64 version of Windows.

For googler that wants to break only when the exception concerns their code, there is an option in Visual Studio 2015: Options->Debugging->General->Just My Code. Once checked, it allow to do not break when the exception is managed (thrown and catched) outside your code.

Microsoft have subtly changed the logic in the new exceptions window.

See http://blogs.msdn.com/b/visualstudioalm/archive/2015/02/23/the-new-exception-settings-window-in-visual-studio-2015.aspx

The key part being:

Important Notes This new window contains all of the same functionality as the old modal dialog. No capabilities of the debugger have changed only the way you can access them The debugger will always break when an exception is unhandled The setting to change if the debugger breaks on user-unhandled exceptions has moved under a context menu The menu location has moved to Debug -> Windows -> Exception Settings

However, if like me you have a Global Unhandled Exception Handler in your code then the second item on that list is key: For me, no exceptions will therefore be truly unhandled, which seems to be different from VS2013.

To get back the behaviour where VS breaks on unhandled exceptions, I had to tick all of the exception types I wanted to break on and then secondly ensure that the "Additional Options" (you may need to make this column visible*) for "Continue when unhandled in user code" was NOT set. The VS2015 logic does not seem to consider my Global Unhandled Exception Handler to be "handled in user code", so it does break on these; it doesn't break on caught exceptions though. This makes it work like VS2013 did.

https://i.stack.imgur.com/AjN3W.png

If I'm correctly reading between the lines here, the issue is that your exception is effectively 'disappearing' even though the default debugger behavior should break on unhandled exceptions.

If you have asynchronous methods, you may be running into this issue because exceptions not caught on a thread pool thread as part of a Task continuation are not considered unhandled exceptions. Rather, they are swallowed and stored with the Task.

For example, take a look at this code:

class Program
{
    static void Main(string[] args)
    {
        Test();
        Console.ReadLine();
    }

    private async static Task Test()
    {
        await Task.Delay(100);
        throw new Exception("Exception!");
    }
}

If you run this program with the default debugger settings (stop on unhandled exceptions only), the debugger will not break. This is because the thread pool thread allocated to the continuation swallows the exception (passing it to the Task instance) and releases itself back to the pool.

Note that, in this case, the real issue is that the Task returned by Test() is never checked. If you have similar types of 'fire-and-forget' logic in your code, then you won't see the exceptions at the time they are thrown (even if they are 'unhandled' inside the method); the exception only shows up when you observe the Task by awaiting it, checking its Result or explicitly looking at its Exception.

This is just a guess, but I think it's likely you're observing something like this.

In my experience the exception settings in 2015 get thrown completely out of whack if you change anything.

On expect that if you until the parent group "CLR" then you shouldn't get any breaking execpt for unhandled. You'll always break if an exception goes unhandled. But, if you have the CLR group unticked, code inside a try...catch simply should not cause a break. That is NOT the case.

Solution: In the new exception settings toolbox, right-click and choose "restore default". Taadaaaa... It behaves normally again. Now don't screw with it.

Try following the instructions:

In the Exception Settings window, open the context menu by right-clicking in window and then selecting Show Columns. (If you have turned off Just My Code, you will not see this command.) You should see a second column named Additional Actions. This column displays Continue when unhandled by user code on specific exceptions, meaning that the debugger does not break if that exception is not handled in user code but is handled in external code. You can change this setting either for a particular exception (select the exception, right-click, and select/deselect Continue when Unhandled in User Code) or for an entire category of exceptions (for example, all the Common Language Runtime exceptions).

https://msdn.microsoft.com/en-us/library/x85tt0dd.aspx

It's all a bit confusing, and in my opinion not as good as the old exceptions dialog, but anyway.

If an exception is in the list and ticked then the debugger will break whenever the exception is thrown.

If an exception is unticked or not in the list then the debugger will only break when that exception type is user unhandled.

For example, in the screenshot below, the debugger will break whenever a System.AccessViolationException is thrown, but for all the other exceptions it will only break if the exception was user unhandled.

https://i.stack.imgur.com/f1tz3.png

When I upgraded to VS2015, I also had issues where exceptions used to "break" the application, but are now ignored and passed right over. There are times when we want our code to intentionally throw exceptions in places where we want the code to stop, rather than continue. We always use the phrase Throw New Exception("Message") to get our code to intentionally break:

    If SomethingReallyBad = True Then
        Throw New Exception("Something Really Bad happened and we cannot continue.")
    End If

With VS2015, the classic "System.Exception" is what is thrown when we say Throw New Exception. Therefore, we needed to check the "System.Exception" tick in the new Exception Settings:

Check the System.Exception Box

Once checked, our code did as expected.

The solution is to this is semantically the opposite to what you think you are setting. You need to ensure that Continue when unhandled in user code is not enabled i.e. not checked as shown under the Additional Actions column in the Exception settings tab - see below:

you are effectively saying do not continue (i.e. break) when unhandled in code

https://i.stack.imgur.com/6bJTo.png

To do this:

Right click the exception or set of exceptions that you care about (i.e. usually the top line 'Common Language Runtime Exceptions' in the tree) Select the option Continue When Unhandled in User Code (see below) Ensure that the exceptions are not checked (see below) continue debugging

https://i.stack.imgur.com/ICLuz.png

That did it for me - happy again.

This was in VS 2015

There's definitely some bug in Visual Studio that can cause it to get stuck requiring a restart. Even VS2015.

I had a single threaded situation where a NullReferenceException was getting caught by an 'outer' handler (still in my code) even though I asked for it to break when it was raised.

I realize this is a 'handled' exception and you're talking an 'unhandled' one - however I'm pretty sure that sometimes a quick restart of VS will fix this, if IISRESET doesn't.

Visual Studio 2017 works just fine with error handling. Visual Studio 2015 on the other hand sucks at error handling with tasks because in debug mode all exceptions that occur in an async task are caught but then if I step over it just hangs indefinitely. If executed without debugging it hangs indefinitely with no exception caught!!! I love visual studio and have been using it since 1995 and 2015 is the worse version by far though I jumped from 2010 directly to 2015. I spent 8 hours trying to get this exception handling working with no success. I copied the exact code to 2017 on my home computer and it worked perfectly. I am very irritated that Microsoft pushed tasks into a framework that the 2015 compiler can't handle correctly.