How to fix error "ANCM In-Process Handler Load Failure"?

Open the .csproj file and under Project > PropertyGroup > AspNetCoreHostingModel, change the value “InProcess” to “OutOfProcess”.

<PropertyGroup>
<TargetFramework>netcoreapp2.2</TargetFramework>
<AspNetCoreHostingModel>OutOfProcess</AspNetCoreHostingModel>

I had the same error.

According to Microsoft(https://dotnet.microsoft.com/download/dotnet-core/current/runtime), We should install the 'ASP.NET Core Hosting Bundle' in our hosting server.

'The ASP.NET Core Hosting Bundle includes the .NET Core runtime and ASP.NET Core runtime. If installed on a machine with IIS it will also add the ASP.NET Core IIS Module'

After I did, The 'AspNetCoreModuleV2' installed on my server and everything works well. It didn't need to change your 'web.config' file.

Sometimes this is because multiple applications may be using same Application Pool

In such cases first application will work and other won't work

Solution is to create new application pool for each application.

For more info, in web.config, set

stdoutLogEnabled="true"

then check the logs folder. In my case it had nothing to do with project, publishing or hosting settings - it was my fault for not copying a file essential to my app. The error was simply "Could not find file "D:\Development\IIS Hosting Test\filename.ext"

For my particular issue it was the site permissions in IIS.

I edited the permissions to "Everyone" and it worked. I got the information from this page: https://github.com/aspnet/AspNetCore/issues/6111

I faced with the same issue today, installing the following package on server is fixed the issue for me. If you have any previous version of Windows Hosting Bundle already installed on the server, you install the new one without restarting the server.

ASP.NET Core 3.1 Runtime (v3.1.11) - Windows Hosting Bundle

In my case updating .net core sdk works fine.

I fixed this here Asp.Net Core Fails To Load - you need to specify that the program uses an in process or out of process model.

I changed my CreateWebHostBuilder to:

public static IWebHostBuilder CreateWebHostBuilder(string[] args) 
{
    var env = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");
    var builder = WebHost.CreateDefaultBuilder(args);

    if (env == EnvironmentName.Staging || env == EnvironmentName.Production)
        builder.UseIIS();

    builder.UseStartup<Startup>();
    return builder;
}

PS. I set ASPNETCORE_ENVIRONMENT in my .pubxml deployment profile by adding:

<PropertyGroup>
    <EnvironmentName>Staging</EnvironmentName>
</PropertyGroup>

You can get this if you try to access the site using a IIS url but Visual Studio is setup to use IISExpress

See also ASP.Net Core 1.0 RC2 : What are LAUNCHER_PATH and LAUNCHER_ARGS mentioned in web.config?

Long story short, the web.config is changed by Visual Studio when you switch between IIS and IISExpress. If you use an IIS url when it's setup to use IISExpress then the aspNetCore processPath will be wrong

Also, it's not uncommon to copy web.config files. You could get the same error if you don't change the processPath

For me it was because I had ASPNETCORE_ENVIRONMENT environment variable being defined 2 times in my app - one in web.config and another - in applicationhost.config

In my case just adding MVC into Startup.cs Please follow into image. I am trying to add dependency injection then showing this problem. I think it will be helpful. Follow this Image: https://i.stack.imgur.com/ykw8P.png

Delete the 'hosting Model ="in process"' section in web config.

Example:

<aspNetCore processPath="dotnet" arguments=".\WebAPICore.dll" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" hostingModel="inprocess" />

to

<aspNetCore processPath="dotnet" arguments=".\WebAPICore.dll" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" />

I'm also getting "HTTP Error 500.0 - ANCM In-Process Handler Load Failure"

Except in my case...Everything was running great until I got the Blue Screen of Death.

I have a solution with two startup projects.
One is an API (that comes up) and the other is a WebApp(which gets the error). Both are .NET Core 3.1..also VS2019.

First I tried setting a break point in Main() of program.cs...it never got this far.

 public static void Main(string[] args)
 {
     CreateHostBuilder(args).Build().Run();
 }

On a hunch...I Looked at the NuGet packages installed. I uninstalled and (re)installed

Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation(3.1.6)

...and now its working again.

In case anyone else cannot find a solution to this here was my scenario:
I recently started a new project using .NET 5, and everything was working. Then I upgraded from Preview 5 to 7 and all of a sudden my IIS Express would no longer work. The fix for me was to simply repair Visual Studio:

.

I belive that IISExpress got messed up along the way.

Try the following:

'Clean Solution' from VS
Got to the solution folder and delete the .vs folder from there.
Build and run.

This happened to me when I switched form debugging in IIS Express to IIS. I inspected Event Viewer > Application log, and found the following error there:

Executable was not found at '...\bin\Debug\netcoreapp3.1\%LAUNCHER_PATH%.exe'

I then found the solution to that in the following thread.

I basically needed to replace web.config entry with hard-coded name of the application:

<aspNetCore processPath="dotnet" arguments=".\ProjectName.dll" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" forwardWindowsAuthToken="false"/>

I get that error when i try to get data from the ViewModel as List<> and my data is coming as IEnumerable format. Before u guys update your vs2019 or delete some files,u should better to check it out that option.

For me it was caused by different web.config files for development and deployment :

development: <aspNetCore requestTimeout="23:00:00" processPath="%LAUNCHER_PATH%" arguments="%LAUNCHER_ARGS%" forwardWindowsAuthToken="false" stdoutLogEnabled="true" stdoutLogFile=".\logs\stdout" startupTimeLimit="3600" hostingModel="InProcess">

deployment : <aspNetCore requestTimeout="23:00:00" processPath=".\Nop.Web.exe" arguments="" forwardWindowsAuthToken="false" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" startupTimeLimit="3600" hostingModel="InProcess">