This was my thought also. But i can't use the workaround because a .net standard project doesn't have this folder/file. I tried to copy the .dll files by hand to > C:\\Users\\$User\\source\\repos\\Echo\\DataLibrary\\bin\\Debug\\netstandard2.1\\x86 C:\\Users\\$User\\source\\repos\\Echo\\DataLibrary\\bin\\Debug\\netstandard2.1\\x64 but with no luck and at the moment i am pretty clueless what to do next. When i run > dotnet build --version i get >Microsoft (R)-Build-Engine, Version 16.10.1+2fd48ab73 für .NET >Copyright (C) Microsoft Corporation. Alle Rechte vorbehalten. > >16.10.1.27001 although i am using VS 16.10.3. I dunno how the change this. Everything should be up to date.