Building Core2.0 project in Visual Studio Team Services fails with numerous assembly import errors

Question

I have Build Definition

• .NET Core Restore
• .Net Core Build
• .Net Core Test
• .Net Core Publish
• Publish Artefact

While I was using Core1.1 it worked without any issue. But after upgrading project to Core2.0 it fails with multiple errors like

• error CS1703: Multiple assemblies with equivalent identity have been imported: 'C:\Users\buildguest\.nuget\packages\microsoft.netcore.app\2.0.0\ref\netcoreapp2.0\System.Threading.Tasks.Parallel.dll' and 'C:\Users\buildguest\.nuget\packages\system.threading.tasks.parallel\4.3.0\ref\netstandard1.1\System.Threading.Tasks.Parallel.dll'
• error CS0433: The type 'TargetFrameworkAttribute' exists in both 'System.Runtime, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' and 'System.Runtime, Version=4.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
• error CS0518: Predefined type 'System.String' is not defined or imported

Solution is perfectly building locally. I tried to add task Use .NET Core runtime 2.0.0 in the beginning but without any success.

Answer 1

You should add .NET Core Tool Installer task at the beginning of the build steps. Then install the SDK not only runtime. Then save your build definition and queue again.