I got my very first Mac in March this year. I have a 13" MacBook Air (2.13Ghz Intel Core 2 Duo) running Snow Leopard 10.6.8. Last month I set up a Time Machine using a Transcend StoreJet 640Gb - I used disk utility to format the drive to Mac OS Extended (Journaled). In Time Machine, I can see entries going back to 08 August 2011. Today after working on a document for 3 hours, Word for Mac kindly crashed on me. My Autorecovery did not save a version of the document (I checked all autorecovery files) and the 'Rescued Document' was unusable. I then tried using Time Machine to see if I could get an earlier version of the document which might hopefully have a document that was 2/3rds done but discovered to my horror that although Time Machine seems to show entries back to 08 August, I could only access entries for the past 2 hours today. What am I doing wrong?