---
title: "Why am I hitting deadlocks with async/await in my ASP.NET Core Web API controllers?"  
description: "Why am I hitting deadlocks with async/await in my ASP.NET Core Web API controllers?"  
author: "Anubhav Sharma"  
published: 2026-09-20  
updated: 2026-09-20  
canonical: https://www.mindstick.com/forum/162187/why-am-i-hitting-deadlocks-with-async-await-in-my-asp-net-core-web-api-controllers  
category: "Asynchronous Programming"  
tags: ["c#", "web development", "performance"]  
reading_time: 1 minute  

---

# Why am I hitting deadlocks with async/await in my ASP.NET Core Web API controllers?

I've been refactoring a legacy Web API recently, and after switching several endpoints to use `async Task` and `await`, I'm suddenly seeing sporadic 500 errors that look like deadlocks. The stack traces mention `SynchronizationContext` and `TaskScheduler`, which I don't fully understand.

My controllers are inheriting from `ControllerBase` in a standard ASP.NET Core app. I'm calling EF Core `SaveChangesAsync()` and some third-party HTTP clients with `await`, but I'm not sure if I'm doing something wrong with the context capture or if it's something else entirely.

Has anyone else run into this? What are the common pitfalls when moving from synchronous to asynchronous controller actions in this framework?


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Original Source: https://www.mindstick.com/forum/162187/why-am-i-hitting-deadlocks-with-async-await-in-my-asp-net-core-web-api-controllers

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