This is not a bug in Gestalt - it is a documented limitation. OS: OSX 10.11.1 Exiftool: 10.03 directly loaded and 10.01 over homebrew pyExitToolGui: Full Package Console log 27.10.15 13:36:53,084 pyexiftoolgui: WARNING: The Gestalt selector gestaltSystemVersion is returning 10.9.1 instead of 10.11.1. After choosing exiftool, which is the latest version (10.03), the programm quits and relaunching it, just repeats the not found process. Visit for free, full and secured software’s. ExifTool for Mac OS X 11.18 - Renames files and organizes in directories - offers free software downloads for Windows, Mac, iOS and Android computers and mobile devices. Download the latest versions of the best Mac apps at safe and trusted MacUpdate. ExifTool 11.21 - Manipulate image, audio, and video metadata.