Could not find a part of the path ... bin\roslyn\csc.exe
I am trying to run Asp.net MVC project retrieved from TFS source control. I have added all assembly references and I am able to build and compile successfully without any error or warning.
But I get the following error in the browser:
Could not find a part of the path 'C:\B8akWorkspace\B8akProject\B8akSolution\B8AK.Portal\bin\roslyn\csc.exe'.
Here is a full screenshot of the error page.
After few days of research, I understood that Roslyn is .Net compiler platform that offers advance compiling features. However, I do not understand why my build is trying to find \bin\roslyn\csc.exe because I did not configure anything related to Roslyn nor I intend to use Roslyn in my project.
Answer
TL; DR
run this in the Package Manager Console:
Update-Package Microsoft.CodeDom.Providers.DotNetCompilerPlatform -r
More information
This problem is not related to Visual Studio itself, so answers suggesting adding build steps to copy files over are rather a workaround. Same with adding compiler binaries manually to the project.
The Roslyn compiler comes from a NuGet package and there is/was a bug in some versions of that package (I don't know exactly which ones). The solution is to reinstall/upgrade that package to a bug-free version. Originally before I wrote the answer back in 2015 I fixed it by installing following packages at specific versions:
- Microsoft.Net.Compilers 1.1.1
- Microsoft.CodeDom.Providers.DotNetCompilerPlatform 1.0.1
Then I looked into .csproj and made sure that the paths to packages are correct (in my case ..\..\packages\*.*) inside tags <ImportProject> on top and in <Target> with name "EnsureNuGetPackageBuildImports" on the bottom. This is on MVC 5 and .NET Framework 4.5.2.