Entity Framework - Cannot convert lambda expression to type 'string' because it is not a delegate type

Question

I am using Entity Framework in my C# based code. I am running into an unexpected weirdness and am looking for suggestions.

Case 1, 2, 3, 4... Projects:
RivWorks

Answer 1

I had this problem in a slightly different version.
Should you call a (static) method from inside your lambda, check its return type. If the return type should be an IEnumerable (which often is true when using lambdas) but you return object, obviously you have a problem.