Started with a GEN 8.6 Web client program linked with an external C# program that has worked fine so far. After some changes in the C# program, a change was made in Visual Studio's project Target Environment from .net framework 4.0 to .net framework 4.6.1 in order to support some reporting modules that are needed.
After that, The GEN Build Tool returned an error.
"The primary reference "CISW4" could not be resolved because it was built against the ".NETFramework,Version=v4.6.1" framework. This is a higher version than the currently targeted framework ".NETFramework,Version=v4.0". C:\Models\CIS.ief\c#\CISW.csproj]"
Release : 8.6
Component : Gen Build Tool