Problem: I was copying logical files (LF) to another library, when I faced this problem; the copied LF was still pointing to a physical file (PF) in another library. My search brought me to the following article. Its wonderful how you can still learn something new even after years of experience. https://www.itjungle.com/2004/09/08/crtdupobj-and-logical-files/ I hope this article is useful to you and saves you lots of difficult problems in your work. We RPG programmers use lots of logical files to read and update data. Its difficult to trace errors where our programs are referring to data in libraries not even on the library list!. Happy coding!!!