Dear IDL Experts, I keep adding a specific directory with all my functions into the IDL Path by using Windows->Preferences->IDL->Paths->Insert. The path stays there for a while (sometimes even for few session, I remember) then it suddenly disappears. Mostly, I had to add this path each time when I open IDL.. I also tried a startup file (under Windows->Preferences->IDL->Startup File), that adds this directory to the path but looks like IDL does not care about startup file and does not want to keep this directory in its path. My startup file has a line: !PATH = !PATH + PATH_SEP(/Search_Path) + Expand_Path('+C:\Users\......\IDL\IDLLib\') I appreciate your suggestions for figuring out how to add a path permanently. I suppose once a path is added, it should stay there until I delete. Best regards, - Nevzat