At present, developers are unable to debug the .NET modules in AutoCAD 2017 with VS 2015. As explained in Kean’s article for VS 2013 http://through-the-interface.typepad.com/through_the_interface/2013/11/debugging-autocad-using-visual-studio-2013.html , the workaround for this issue is to either enable the native debugging or using the Compatibility mode in VS 2015.
- Turn on “Use Managed Compatibility Mode” via Tools –> Options –> Debugging.
- Turn on “Enable native code debugging” from Project –> Properties –> Debug.