Welcome to MongoDB Community forums. Are you simply trying to convert a collection to a list? You can try something like var restaurantsList = _restaurantsCollection.AsQueryable<Restaurant>().ToList() If you would like to continue using LINQ2, you can switch to the LINQ2 provider using the steps seen here. However, please note that the LINQ2 provider will be deprecated in the next major version of the driver. Hope that helps.
Thanks,
Rishit.