HTTP Error 500.31: Failed to Load ASP.NET Core Runtime – Causes and Fixes

When working with ASP.NET Core applications, one of the most frustrating issues you may encounter is the HTTP error 500.31 – Failed to load ASP.NET Core runtime. This error can appear when deploying your application to IIS or running it locally via IIS Express or Visual Studio. In this article, we will break down the common causes of this error and provide actionable fixes.

What is HTTP Error 500.31?

The HTTP error 500.31 – Failed to load ASP.NET Core runtime typically indicates that the application is unable to find or load the correct ASP.NET Core runtime version. This issue often arises when you deploy or run an ASP.NET Core application but the runtime isn’t correctly installed or configured on the server.

IIS and HTTP Error 500.31

If you’re seeing the IIS HTTP Error 500.31 – Failed to Load ASP.NET Core Runtime, it could mean that your server is missing the required runtime version or that it’s improperly configured. Versions such as HTTP error 500.31 – failed to load ASP.NET Core runtime .NET 6, or newer ones like HTTP error 500.31 – failed to load ASP.NET Core runtime .NET 8, are often affected if the runtime version doesn’t match the application’s requirements.

Common Causes of HTTP Error 500.31

Several reasons can lead to the HTTP error 500.31 – Failed to load ASP.NET Core runtime, including:

• Missing runtime installation (e.g., .NET 5.0, .NET 6.0, .NET 7, .NET 8).
• Incorrect version of the ASP.NET Core Hosting Bundle.
• Misconfiguration in Visual Studio, especially with versions like HTTP error 500.31 – failed to load ASP.NET Core runtime Visual Studio 2022 and HTTP error 500.31 – failed to load ASP.NET Core runtime Visual Studio 2019.
• Using an outdated version of IIS Express or Plesk.

Troubleshooting and Fixes for HTTP Error 500.31

Here are some common solutions to resolve the HTTP error 500.31 – failed to load ASP.NET Core runtime issue:

1. Verify .NET Core Runtime Installation

One of the main reasons for HTTP error 500.31 – Failed to load ASP.NET Core runtime is that the required .NET runtime version isn’t installed. Ensure that the appropriate runtime, such as .NET 6.0, .NET 7, or .NET 8, is correctly installed on your server. If the runtime isn’t available, download and install it from the official Microsoft website.

2. Update ASP.NET Core Hosting Bundle

The ASP.NET Core Hosting Bundle is essential for running applications in IIS. Ensure that the hosting bundle version matches the ASP.NET Core runtime your application needs. For example, if you’re deploying an application using HTTP error 500.31 – Failed to load ASP.NET Core runtime .NET 5.0 or newer versions like .NET 8, make sure your server has the right hosting bundle installed.

3. Check Visual Studio Configuration

For those working in Visual Studio, mismatches between the IDE and the installed runtime can trigger the HTTP error 500.31 – failed to load ASP.NET Core runtime Visual Studio 2022 or older versions like 2019. Ensure that Visual Studio is correctly configured with the necessary SDKs and runtimes.

4. Fix IIS and IIS Express Configurations

Issues can also arise due to incorrect settings in IIS or IIS Express. If you encounter HTTP error 500.31 – failed to load ASP.NET Core runtime on IIS, ensure that the web.config file is correctly configured and points to the correct ASP.NET Core runtime version.

5. Plesk Hosting Troubleshooting

For those using Plesk, the HTTP error 500.31 – failed to load ASP.NET Core runtime Plesk can occur if the necessary components are missing or misconfigured. Updating Plesk and ensuring compatibility with the ASP.NET Core runtime should resolve the issue.

Common Scenarios for HTTP Error 500.31

1. IIS HTTP Error 500.31 – Failed to Load ASP.NET Core Runtime
   • This error often occurs when deploying an ASP.NET Core application on IIS without the necessary runtime installed.
2. HTTP Error 500.31 – Failed to Load ASP.NET Core Runtime in Visual Studio
   • Developers might encounter this issue when running applications in Visual Studio if the targeted .NET runtime is missing or mismatched.
3. Specific .NET Version Issues
   • Errors like HTTP Error 500.31 – Failed to Load ASP.NET Core Runtime .NET 6 or HTTP Error 500.31 – Failed to Load ASP.NET Core Runtime .NET 8 can occur if the specified version is not installed on the system.

Common Solutions to HTTP Error 500.31

• Install the Required .NET Runtime: Ensure that the correct version of the .NET runtime, such as .NET 6, .NET 7, or .NET 8, is installed on your machine.
• Configure IIS Properly: Verify that IIS is configured correctly to host ASP.NET Core applications by installing the appropriate hosting bundle.
• Check Visual Studio Settings: In Visual Studio, ensure that the project settings target a version of .NET that is installed on your development machine.
• Update Application Configuration: Review and update your application’s configuration files to match the installed runtime versions

Related Questions & Answers

This article will help developers resolve the HTTP error 500.31 when working with ASP.NET Core applications in various environments like IIS, Visual Studio, and Plesk, across multiple .NET versions.