http://blogs.msdn.com/marcelolr/archive/2008/08/22/entitystate-problems-in-ado-net-data-service.aspxIf you're getting an error in your ADO.NET Data Service about 'EntityState' not being a valid property, this is the likely cause. The entity types generated by the ADO.NET Entity Framework include a number of properties that help you manage the entityen-USCommunityServer 2.1 SP1 (Build: 61025.2)