For Mac users: Finder windows normally show you an accurate view of what’s in your folders, but occasionally, if something happens behind its back, the Finder doesn’t update the window immediately. This is most common on network shares, and happens on Windows as well. Windows has the F5 key to refresh the current view, though, and there isn’t a Finder equivalent.
Rainer Brockerhoff’s Nudge utility will do the same thing for Mac users.
How to find your updats that as been download
and back it up an a CD or save it