If you are opening your file and suddenly encounter a pop up dialog box with message similar to this: Unable to find tilt file ''NONE...


You can fix it by opening the IES file with a text editor (Notepad or Scite), remove any spacing after the text TILT=NONE, then save as a new IES file (be sure the file extension is .ies). You should then able to open your file without error and it should render fine as well.