Why do unawaited async methods not throw exceptions?

Question

I thought that async methods were supposed to behave like normal methods until they arrived at an await.

Why does this not throw an exception?

Is there a way to have the exception thrown without awaiting?

using System;
using System.Threading.Tasks;

public class Test
{
    public static void Main()
    {
        var t = new Test();
        t.Helper();
    }

    public async Task Helper()
    {
        throw new Exception();
    }
}

As a historical note, exceptions were originally raised "directly" as you expect. However, this behavior was confusing because exceptions before and after the `await` would behave differently, and it could get *really* confusing if the `await` was conditional. — Stephen Cleary, Jun 27 '14 at 01:15
@Craig, one other option is to use `async void`, check ["Fire and Forget approach"](http://stackoverflow.com/q/22864367/1768303). — noseratio, Jun 27 '14 at 12:43

i3arnon · Accepted Answer · 2014-06-26T23:56:53.233

An exception thrown inside an async method is, by design, stored inside the returned task. To get your hands on the exception you can:

await the task: await t.Helper();
Wait the task: t.Helper().Wait();
Check the task's Exception property after the task has been completed: var task = t.Helper(); Log(task.Exception);
Add a continuation to that task that handles the exception: t.Helper().ContinueWith(t => Log(t.Exception), TaskContinuationOptions.OnlyOnFaulted);

Your best option is the first one. Simply await the task and handle the exception (unless there's a specific reason you can't do that). More in Task Exception Handling in .NET 4.5

Why do unawaited async methods not throw exceptions?

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