I created some stock structural steel extrusions w/ INV 11 for company use. Now when I open the individual parts and try to edit the feature length, I get an error message: "Cannot modify the library file M:\Inventor Library\W Shapes\w8-18.ipt" This is a bit disconcerting since I created hundreds of stock extrusions for structural steel components. I can insert them into an assembly, but cannot edit them individually to modify lengths. What can I do to get these parts fixed? Does it have something to do with the "lock" files I find in the directories?