Okay, recently got a .sit file on my sister macbook, downloaded Stuffit Expander, and it worked fine, that was a week ago. Today, more .sit files, and Stuffit expander won't open at all. The icon struggles to show in the dock, and the icons already there move as if to make room for it, but it dissapears just as quickly. Ideas? EDIT: I know for a fact it keeps crashing upon execution, no idea why it would work one day and not the other. I've uninstalled and reinstalled it, but no dice.