You have multiple concrete types that implement the same interface

###Situation With the default behaviour of the Automapper, it expects to find one and only one implementation of a given interface. If you have several concrete types that map to an interface, it will throw a DuplicateMappingException.

###Example

         public interface IMyService { }
         public class MyService : IMyService { }
         public class MyOtherService : IMyService { }

###How do I fix this?

You have several options: -

1. If you intend to only use one of these implementations at runtime, mark the other one with the [DoNotMap] attribute (or fluent equivalent).
2. If you want to access all implementations at runtime, either: -
   • Mark the interface as a [Multimap] (or fluent equivalent)
   • Use the MultimapByDefault mapping behavior when calling the Automapper. See here for more details on Multimaps.