I created a new model :
ADO.NET Entity Data Model
EF Designer from database .
When I changed the Code generation from T4 to Legacy objectContext
I got :
The type or namespace name 'EntityClient' does not exist in the namespace 'System.Data'
The type or namespace name 'Objects' does not exist in the namespace 'System.Data'
The type or namespace name 'EdmSchemaAttribute' could not be found
Any idea how can I resolve this?