Join our CAD community forums where over 25,000 users interact to solve day to day problems and share ideas. We encourage you to visit, invite you to participate and look forward to your input and opinions. Acrobat 3D, AutoCAD, Catia, Inventor, IronCAD, Creo, Pro/ENGINEER, Solid Edge, SolidWorks, and others.
Make sure that in Tools, Options, PartInfrastructure, Display that External Referenes + Relations + Parameters are active. Maybe in your case not all three are necessary but it's not a bad idea having them all switched on.