[Solved] Unity 5.6.3f1 + Monodevelop --> Unsupported MsBuild version 12.0

Build & Deployment
1

I’ve started experiencing this issue when using monodevelop:

Build failed. Unsupported MSBuild ToolsVersion 'dotnet.12.0'
Build: 1 error, 0 warnings

I think it started when I removed Visual Studio 2013 (I still have Visual Studio 2015). The project in question uses Monodevelop, and I was under impression that it wasn’t supposed to attempt to launch external tools.

Inside monodevelop there’s a “Use msbuild engine” checkbox, and if it is unset, project compiles, BUT once unity regenerates solution files the checkbox is set again.

Looking through *.csproj files, it seems that the “UseMSBuildENgine” isn’t even within the settings, and apparently it is defined somewhere else as a default.

How do I fix this?

2

Alright. So… installing MSVS2013 does not fix the issue. installing visual studio 2017 build tools for .NET does not fix the issue. The problem is not really mentioned anywhere on the web, aside from one thread on unity forums where it is unanswered.

The project compiles in 2017.1, however I’ll need to work with older versions too, and if installing 2017.1 breaks older version, it is bad.

So, can someone from unity staff chime in and give some ideas? @superpig , @Buhlaine , or someone else?

3

I had a quick look in the MonoDevelop source code to see where this exception is thrown.

https://github.com/Unity-Technologies/monodevelop/blob/unity-trunk-patch-staging/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.Formats.MSBuild/MSBuildProjectService.cs#L644

This exception should only be throw in if the file
bin\MSBulid\dotnet.12.0\MonoDevelop.Projects.Formats.MSBuild.exe

does not exist. This file is part of the MonoDevelop build we ship and I’ve verified locally that I have this file.

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4

Thanks to this information, I’ve figured out what went wrong.

The file in dotnet.12.0 is indeed gone, and it turns out it was silently deleted by my avast antivirus. This isn’t the first time something like this happens, so I think I’ll be installing different antivirus.

Thanks for the assistance.

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