I have Leopard and an external FreeAgent HD. I have Quicken on the external and all my spreadsheets and letters on the Leopard I updated one of the six spreadsheets and when I went back this morning everything is gone. No pages (letters) and no spreadsheets. At first I too thought it was the hidden extension but I've tried every type of utility and finder search for file names and documents on both HD and external. NADA. Any idea how in the world you could lose all your documents? I have never understood Time Machine. I looked there and tried to reinstall backups from the first of the month but the only thing in Time Machine is the program itself, none of the spreadsheets or letters. Bummer. I'm still struggling with the conversion from Windows ... Have been using the Mac for over a year now and love it but somethings are difficult to learn after many years on PC's.