Why can't Visual Studio 2017 find installed .NET Core SDKs? - visual-studio

Question

I have a simple project which builds with "dotnet build" and with msbuild from the Visual Studio 2019 Developer prompt, but not from the Visual Studio 2017 prompt or IDE. I would like to understand how msbuild 15 finds the installed SDKs and why they are not up to date, while msbuild 16 in VS 2019 works ok.
It appears that the .NET Core SDKs are not registered with msbuild 15 but I don't know how that registration occurs. I have tried reinstalling the SDK, installing different versions of the SDK, but no luck so far.
Unfortunately just switching to 2019 is difficult because what I really want is to compile a large code base with a build script which assumes 2017 - this is a cut-down repro.
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>netcoreapp2.0</TargetFramework>
</PropertyGroup>
</Project>
Compiling from VS2017 developer prompt:
msbuild foo.csproj /nologo
Build started 5/20/2019 7:22:06 AM.
Project "C:\Users\edwin\Source\Repos\foo\foo.csproj" on node 1 (default targets).
C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild\Sdks\Microsoft.NET.Sdk\build\Microsoft.NET.TargetFrame
workInference.targets(112,5): error : The current .NET SDK does not support targeting .NET Core 2.0. Either target .NET Cor
e 1.1 or lower, or use a version of the .NET SDK that supports .NET Core 2.0. [C:\Users\edwin\Source\Repos\foo\foo.csproj]
Done Building Project "C:\Users\edwin\Source\Repos\foo\foo.csproj" (default targets) -- FAILED.
Compiling in same window with "dotnet build" succeeds, as does "msbuild foo.csproj" in the 2019 developer prompt (which uses msbuild 16).
dotnet --info shows
.NET Core SDK (reflecting any global.json):
Version: 2.2.204
Commit: 8757db13ec
Runtime Environment:
OS Name: Windows
OS Version: 10.0.17763
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\2.2.204\
Host (useful for support):
Version: 2.2.5
Commit: 0a3c9209c0
.NET Core SDKs installed:
1.0.3 [C:\Program Files\dotnet\sdk]
2.1.104 [C:\Program Files\dotnet\sdk]
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.402 [C:\Program Files\dotnet\sdk]
2.1.403 [C:\Program Files\dotnet\sdk]
2.1.604 [C:\Program Files\dotnet\sdk]
2.2.204 [C:\Program Files\dotnet\sdk]

Answer 1

I experienced this issue 4 days ago when I was using Visual Studio 2017. And I spent all the days to solve it. After searching, on internet,I realised that it was a versioning issue.
verytime, I tried to create a new project I had this message:
The SDK 'Microsoft.NET.Sdk.Web' specified could not be found.
So, I decided to delete all the .Net Core SDK versions and installed the compatible one as indicated on the download Page. See the image below.
[
After installing it, everything started working fine.