The mapping of CLR type to EDM type is ambiguous with EF 6 & 5?

Solution 1:

Don't use classes with the same unqualified name - EF uses only class names to identify the type mapped in EDMX (namespaces are ignored) - it is a convention to allow mapping classes from different namespaces to single model. The solution for your problem is to name your classes in BLL differently.

Solution 2:

Workaround: Change a property on one of the two identical classes.

EF matches on class name AND class properties. So I just changed a property name on one of the EF objects, and the error is gone.

As @Entrodus commented on one of the other answers:

EF collision happens only when two classes have the same name AND the same set of parameters.

Solution 3:

This MSDN forum question might be helpful. It suggest placing the BLL and DAL classes in separate assemblies.