I created this Office2 HD *.xls file several days ago and saved it many times before. Just an hour ago the file was hung and I can't move the cursor at all. So I tried clicking the 'close' button to save it. Then the file was gone and the error message pop up saying there was something error. After that I looking for the file from the list in local files but I can't find it at all. I've tried resetting the iPad but still can't find it. This file is not new as I used it many time and update many time as well, why it's disappear like that! Can anyone explain what's happened? How could I recover the file? THX.