Try the following: - Make sure that you include "compile_opt idl2" at the beginning of your program. - When you build a sav file, do not use "resolve_all. /continue_on_error." Just open your .pro in a clean IDL-only session, compile it, and then do a save, filename=’mysavfile’, /routines. - In testing it, if you have any library routines (IDL or ENVI) that aren’t being recognized at runtime, rebuild the save file using a forward_function call specifying only the routines that were not recognized. That *should* do the trick....