title: Intellisense not working in VSCode - OmniSharp Error
body: <p>Intellisense has stopped working for me and whenever I run VSCode this error comes up in the OmniSharp Log.</p>
  <pre><code>[warn]: OmniSharp.MSBuild.ProjectManager
          Failed to load project file '/Users/leogaunt/Documents/Programming/Unity/Cube Stack/Assembly-CSharp.csproj'.
  /Users/leogaunt/Documents/Programming/Unity/Cube Stack/Assembly-CSharp.csproj
  /Users/leogaunt/.vscode/extensions/ms-dotnettools.csharp-1.23.1/.omnisharp/1.37.0/omnisharp/.msbuild/Current/Bin/Microsoft.Common.CurrentVersion.targets(1178,5): Error: The reference assemblies for .NETFramework,Version=v4.7.1 were not found. To resolve this, install the Developer Pack (SDK/Targeting Pack) for this framework version or retarget your application. You can download .NET Framework Developer Packs at https://aka.ms/msbuild/developerpacks
  
  [fail]: OmniSharp.MSBuild.ProjectManager
          Attempted to update project that is not loaded: /Users/leogaunt/Documents/Programming/Unity/Cube Stack/Assembly-CSharp.csproj
  </code></pre>
  <p>I have tried re-installing the plugin, and re-intsalling VSCode but it hasn't worked.</p>
  <p>I know I have .NET Core installed as I am a Mac user and I know this because when I type <code>dotnet --version</code> in terminal it outputs:</p>
  <blockquote>
  <p>3.1.401</p>
  </blockquote>
  <p>I am programming in Unity and am creating a game for iOS.</p>