VS 2026: Docker Compose: Cannot debug ASP.NET Framework 4.7 project with IIS windows container

[kamranayub]

Been using VS 2022 with Container Tools for months now without too much of an issue.

I just upgraded to VS 2026 this week and everything is working... except debugging.

I have a web project that is .NET Framework 4.7.1 and is configured to run under IIS in Windows Server Core 2022.

FROM mcr.microsoft.com/dotnet/framework/aspnet:4.8-windowsservercore-ltsc2022 

# etc...

WORKDIR /inetpub/wwwroot
COPY ${source:-obj/Docker/publish} .

The docker compose project is configured to launch the web project/service:

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" Sdk="Microsoft.Docker.Sdk">
  <PropertyGroup Label="Globals">
    <ProjectVersion>2.1</ProjectVersion>
    <DockerTargetOS>Windows</DockerTargetOS>
    <DockerPublishLocally>True</DockerPublishLocally>
    <ProjectGuid>69dae30f-922a-4e5a-b2a3-3baf4a11c33b</ProjectGuid>
    <DockerLaunchAction>LaunchBrowser</DockerLaunchAction>
    <DockerServiceUrl>http://{ServiceHost}:{ServicePort}</DockerServiceUrl>
    <DockerServiceName>web</DockerServiceName>
  </PropertyGroup>
  <ItemGroup>
    <None Include="docker-compose.override.yml">
      <DependentUpon>docker-compose.yml</DependentUpon>
    </None>
    <None Include="docker-compose.yml" />
  </ItemGroup>
</Project>

I have two profiles, but worth noting I've only been using the first one. I added the second explicitly to try and figure out why VS2026 wasn't working:

{
  "profiles": {
    "Docker Compose": {
      "commandName": "DockerCompose",
      "commandVersion": "1.0",
      "serviceActions": {
        "web": "StartWithoutDebugging",
        "db": "StartWithoutDebugging",
        "api": "StartWithoutDebugging",
        "jobs": "StartWithoutDebugging"
      }
    },
    "Debug Website": {
      "commandName": "DockerCompose",
      "commandVersion": "1.0",
      "composeLaunchServiceName": "web",
      "serviceActions": {
        "api": "StartWithoutDebugging",
        "db": "StartWithoutDebugging",
        "jobs": "StartWithoutDebugging",
        "web": "StartDebugging"
      }
    }
  }
}

One obvious thing I notice is that in VS 2026, the Docker Compose startup settings is not mapping my projects correctly in the GUI:

Notice too how it is not mapping the "StartDebugging" value either for the web service.

I think this is a regression but it's hard to debug. Maybe I'm missing a component in VS2026 installation that I have in VS2022? As a workaround, I can debug still in VS2022.

[kamranayub]

Just wanted to mention, this is still an issue, but I will test the latest 2026 December Update. I've been using VS 2022 instead. I may need to report this on the feedback portal I suppose?

https://developercommunity.visualstudio.com/VisualStudio

[kamranayub]

Logged here: https://developercommunity.visualstudio.com/t/Cannot-debug-ASPNET-MVC5-Framework-in-D/11015986?port=1025&fsid=109e6451-13a1-4f5f-b0da-4494ff72f791