Another computer created a new sub-folder on an external drive attached to an iMac. Using finder, the iMac does not see the new sub-folder. In Windows, I could have the Windows Explorer re-read the directory (and find changes) using F5 or click a icon (like the one in Safari to reload a web page). How can I do this with OS X--re-read the folder so that it sees the new sub-folder ? Thanks, again. Cheers !!