.NET Web API project Error CS1703: Multiple assemblies with equivalent identity have been imported: System.Runtime.Serialization.Primitives.dll

Question

Error CS1703: Multiple assemblies with equivalent identity have been imported: System.Runtime.Serialization.Primitives.dll

I have a C# .Net project was running on .Net framework 4.6 not .Net core, but as required, we upgraded to 4.6.1. Then I can build successfully locally, but once I deploy my changes to VSTS, I got this issue from the build of DevOps. I'm using the latest version of VS, 2017 15.9.7

Here is the detail of the error:

Error CS1703: Multiple assemblies with equivalent identity have been imported: 'D:\a\1\s{ProjectName}\packages\System.Runtime.Serialization.Primitives.4.3.0\lib\net46\System.Runtime.Serialization.Primitives.dll' and 'C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.6.1\Facades\System.Runtime.Serialization.Primitives.dll'. Remove one of the duplicate references.

Answer 1

I had the similar issue, when forgot to tick "Delete all existing files" checkbox before publishing. Enable it in publish profile settings.