title: HTTP Error 500.35 - ANCM Multiple In-Process Applications in same Process ASP.NET Core 3
body: <p>From this morning without any changes to the code of the project, a very simple Web API, one controller and 3 methods, with Swagger, it doesn't start anymore and I get the error:</p>
  
  <blockquote>
    <p>HTTP Error 500.35 - ANCM Multiple In-Process Applications in same Process</p>
  </blockquote>
  
  <p>Event viewer report the most useless message:</p>
  
  <blockquote>
    <p>IIS Express AspNetCore Module V2: Failed to start application
    '/LM/W3SVC/2/ROOT/docs', ErrorCode '0x80004005'.</p>
  </blockquote>
  
  <p>Restarted the system several times.</p>
  
  <p>I'm using Visual Studio 2019, the application successfully compile and a few minutes ago it was working fine. No new software has been installed, no packages added.
  Tried also clean and rebuild.</p>
  
  <p>I've just modified the comment of a method. Obviously I've tried also to restore the previous comment but I get always the same message.</p>
  
  <p>What can I do?</p>
  
  <p>Is net core still too unstable to be used professionally?</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>The same code launched from the same version of Visual Studio but in another PC runs properly.</p>
  
  <p><strong>UPDATE 2</strong></p>
  
  <p>Below the code of the application:</p>
  
  <p>startup.cs</p>
  
  <pre><code>using Microsoft.AspNetCore.Builder;
  using Microsoft.AspNetCore.Hosting;
  using Microsoft.Extensions.Configuration;
  using Microsoft.Extensions.DependencyInjection;
  using Microsoft.Extensions.FileProviders;
  using Microsoft.Extensions.Hosting;
  using Microsoft.OpenApi.Models;
  using System;
  using System.IO;
  using System.Reflection;
  
  namespace WFP_GeoAPIs
  {
      public class Startup
      {
          public Startup(IConfiguration configuration)
          {
              Configuration = configuration;
          }
  
          public IConfiguration Configuration { get; }
  
          public void ConfigureServices(IServiceCollection services)
          {
  
              services.AddControllers(); 
              services.AddSwaggerGen(c =&gt;
              {
                  c.SwaggerDoc("v1", new OpenApiInfo() { Title = "Geographic APIs", Version = "v1.0.0" });
                  var xmlFile = $"{Assembly.GetExecutingAssembly().GetName().Name}.XML";
                  var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);    
                  c.IncludeXmlComments(xmlPath);
              });
          }
  
          public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
          {
              if (env.IsDevelopment())
              {
                  app.UseDeveloperExceptionPage();
              }
  
              app.UseStaticFiles(new StaticFileOptions
              {
                  FileProvider = new PhysicalFileProvider(
                   Path.Combine(Directory.GetCurrentDirectory(), "swagger-ui")),
                  RequestPath = "/swagger-ui"
              });
  
              app.UseHttpsRedirection();
              app.UseRouting();
              app.UseAuthorization();
  
              app.UseEndpoints(endpoints =&gt;
              {
                  endpoints.MapControllers();
              });
  
              app.UseSwagger();    
              app.UseSwaggerUI(c =&gt;
              {
                  c.SwaggerEndpoint("/swagger/v1/swagger.json", "GeoAPIs Ver 1.0.0");
                  c.RoutePrefix = "docs";
                  c.InjectStylesheet("/swagger-ui/custom.css");
              });
          }
      }
  }
  </code></pre>
  
  <p>Here is the launchsettings.json:</p>
  
  <pre><code>{
    "$schema": "http://json.schemastore.org/launchsettings.json",
    "iisSettings": {
      "windowsAuthentication": false, 
      "anonymousAuthentication": true, 
      "iisExpress": {
        "applicationUrl": "http://localhost:51319",
        "sslPort": 44345
      }
    },
    "profiles": {
      "IIS Express": {
        "commandName": "IISExpress",
        "launchBrowser": true,
        "launchUrl": "docs",
        "environmentVariables": {
          "ASPNETCORE_ENVIRONMENT": "Development"
        }
      },
      "WFP_GeoAPIs": {
        "commandName": "Project",
        "launchBrowser": true,
        "launchUrl": "docs",
        "applicationUrl": "https://localhost:5001;http://localhost:5000",
        "environmentVariables": {
          "ASPNETCORE_ENVIRONMENT": "Development"
        }
      }
    }
  }
  </code></pre>
  
  <p>but coping the project on another PC with the same Visual Studio version works fine, so it looks like the is a configuration bug in the .NET Core or VIsual Studio property...</p>