Hi Marie, My guess is that you have one of a few things going on: 1) You have a path that looks into multiple versions of IDL code 2) You have a .sav file that contains a different definition of IDLITMANIPVISVIEW and, when the .sav file is restored, the version of the structure is also restored which means that IDL won't use the structure definition that is in core IDL 3) You have your own structure definition of IDLITMANIPVISVIEW in pro code somewhere and when you compile and run it, then the structure definition is there. These problems are very hard to troubleshoot, but here are some ideas: 1) Try a .full_reset_session or .reset 2) Try upgrading to the latest and greatest version of IDL to see if that solves your problem (IDL 8.5.1). Additionally, what is the value of your path? To get this information, you can type "print, strsplit(!PATH, path_sep(/search_path), /extract)" without the quotes. -Zach (VIS)