When I work on Cocoa programs I read the framework documentation with Xcode’s built in documentation viewer, but sometimes I still open the HTML page for a particular class in Safari with LaunchBar because it is very quick (see this older post).

Xcode downloads these documentation sets from the Internet, and unfortunately all of the thousands of files in there are tagged with the “quarantine” extended file system attribute. This means that the system warns you about potentially harmful content every time you open one of the .html files outside of Xcode, such as in the LaunchBar case.

To get around this, you can clear the quarantine attribute on all files with this command:

find /Developer/Documentation -type f -print0 | xargs -n 100 -0 sudo xattr -d com.apple.quarantine