 <p>System.Data.Entity.dll is not bin deployable. If you have .NET Framework 4 installed on the target machine you should have this assembly. It should be in the GAC. When loading assemblies CLR first looks in GAC and ignores whatever you have in your bin directory. If you don't have the .NET Framework 4 on the target machine your program will not work - System.Data.Entity.dll is part of .NET Framework and depends on .NET Framework (in this case .NET Framework 4). Try removing and readding reference to System.Data.Entity.dll to clear all the changes you made in the project to copy it and then deploy your program to the target machine.</p>