When GISLook or GISMeta suddenly stop working, try restarting your computer. If the Finder still does not show preview icons for your GIS files, do the following:

1. Login with administrator rights and open the Terminal application (it’s in the Utilities directory, which is in the Applications directory)
2. Type “ touch /Library/QuickLook/“ (without quotation marks) and press the Return key.
3. Type “qlmanage -r” (without quotation marks) and press the Return key.
4. Quit the Terminal application.