I tried unzipping a 300MB zip file today using the Mac OS X Archive Utility and nothing happened, no error message, nada.  Then I tried using The Unarchiver and I received an error I’ve never seen before, “error on decrunching”.   So how did I get the zipped file unarchived?  I renamed my file with a new extension, from .zip to .tar.  Then when I used The Unarchiver, voila, my file extracted without a problem.