Hosting .NET 7 application on IIS: Could not load file or assembly 'w3wp' error

Question

I am new to IIS configuration. I'm trying to host my .NET 7 API on IIS but i have an error that i cant solve.

When i try to run my application with IIS, i get this error: "HTTP Error 500.30 - ASP.NET Core app failed to start".

The Event Viewer says:

System.IO.FileNotFoundException: Could not load file or assembly 'w3wp, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
File name: 'w3wp, Culture=neutral, PublicKeyToken=null'
   at System.Reflection.RuntimeAssembly.InternalLoad(AssemblyName assemblyName, StackCrawlMark& stackMark, AssemblyLoadContext assemblyLoadContext, RuntimeAssembly requestingAssembly, Boolean throwOnFileNotFound)
   at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
   at Microsoft.AspNetCore.Mvc.ApplicationParts.ApplicationPartManager.GetApplicationPartAssemblies(String entryAssemblyName)
   at Microsoft.AspNetCore.Mvc.ApplicationParts.ApplicationPartManager.PopulateDefaultParts(String entryAssemblyName)
   at Microsoft.Extensions.DependencyInjection.MvcCoreServiceCollectionExtensions.GetApplicationPartManager(IServiceCollection services, IWebHostEnvironment environment)
   at Microsoft.Extensions.DependencyInjection.MvcCoreServiceCollectionExtensions.AddMvcCore(IServiceCollection services)
   at Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddControllersCore(IServiceCollection services)
   at Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddControllers(IServiceCollection services)

Program.cs -> Line 57 -> "builder.Services.AddControllers();" throw the exception. When i start application, i see w3wp.exe running up. But still i get the error.

What i did so far:

1. Installed IIS on my Windows Server 2019.

2. Installed .Net 7 Hosting Bundle.

3. I publish my app with this settings:

   • Configuration: Release

   • Target Framework: net7.0

   • Deployment Mode: Framework-dependent

   • Target Runtime: Portable

4. Copied the files to this location: C:\inetpub\wwwroot\api.mycompany.com

5. Create my application pool with "No Managed Code". and "Integrated" pipeline mode.

6. Create the site and run it.

7. My web.config file:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <location path="." inheritInChildApplications="false">
        <system.webServer>
            <handlers>
                <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2"
                    resourceType="Unspecified" />
            </handlers>
            <aspNetCore processPath="dotnet" arguments=".\WebApi.dll" stdoutLogEnabled="false"
                stdoutLogFile=".\logs\stdout" hostingModel="inprocess" />
        </system.webServer>
    </location>
</configuration>

With this settings, my application give me the error i mentioned above. However, when i double-click my exe and run it outside of IIS, my app runs perfectly and i can run all get-post request with no error.

What i try to solve the problem:

1. Changed .NET CLR Version to v4.0, failed.

2. Set Enable 32-Bit Applications to true, failed,

3. Changed Managed Pipeline Mode to Classic, failed.

4. Publish my app Self-contained both win-x86 and win-x64, failed.

5. Based on other answers

   • Changed Identity to Local service, failed.

   • Changed Identity to NetworkService, failed.

   • Changed Identity to custom account and logged in as admin user, failed.

   • Set Load User Profile setting to true, failed.

   • Grant IIS_IUSRS and Network Service full access to the directory "C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files", failed.

   • Grant IIS_IUSRS, Network Service full access to project directory, failed.

   • Remove .pdb files on project directory, failed.

   • Start Visual Studio as an administrator and publish my app again, failed.

No matter what i tried it didn't work. What am i doing wrong?

Answer 1

I found the solution. Like @Lex Li said, there is incorrect code on my Program.cs:

var options = new WebApplicationOptions
{
    ApplicationName = Process.GetCurrentProcess().ProcessName,
    ContentRootPath = AppContext.BaseDirectory,
    Args = args
};
var builder = WebApplication.CreateBuilder(args);

Looks like "Process.GetCurrentProcess()" method goes to w3wp. I changed to original version:

var builder = WebApplication.CreateBuilder(args);

After that, my application runs perfectly on IIS.