title: ASP.NET 4.7.2 - Docker - COPY Failed: CreateFile + The system cannot find the file specified
body: <p>I have created a brand new ASP.NET 4.7.2 MVC Web Application using Visual Studio 2019. When initializing the solution in Visual Studio 2019, I selected the <code>Docker support</code> checkbox. This added a file named <code>Dockerfile</code> to my project that looks like this:</p>
  
  <pre><code>FROM mcr.microsoft.com/dotnet/framework/aspnet:4.8-windowsservercore-ltsc2019
  ARG source
  WORKDIR /inetput/wwwroot
  COPY ${source:-obj/Docker/publish} .
  </code></pre>
  
  <p>I attempt to build the Docker image using the <code>build</code> command from a Docker task in Azure DevOps. When I do this, I get the following:</p>
  
  <pre><code>Step 1/13 : FROM mcr.microsoft.com/dotnet/framework/aspnet:4.8-windowsservercore-ltsc2019
    ---&gt; [id1]
  Step 2/13 : ARG source
    ---&gt; Running in [id2]
  Removing immediate container [id2]
    ---&gt; [id3]
  Step 3/13 : WORKDIR / inetpub/wwwroot
    ---&gt; Running in [id4]
  Removing immediate container [id4]
  COPY failed: CreateFile \\?\C:\ProgramData\docker\tmp\docker-build-[id5]\obj\Docker\publish: The system cannot find the path specified.
    ---&gt; [id6]
  STEP 4/13 : COPY ${source:-obj/Docker/publish} .
  </code></pre>
  
  <p>What is wrong? Why did the copy fail? Clearly it's because it "cannot find the file". But, I'm not sure where it should be. I did not change the Dockerfile. I simply tried to build a Docker image from a "Hello World" ASP.NET 4.7.2 web app in Azure DevOps. I'm trying to learn how to use Docker with Azure DevOps.</p>
  
  <p>Thank you</p>