Last night, I did my scheduled backup of my macbook, and changed some preferences in itunes, so that I could also backup my music library on a cd. Afterwards, I restarted my computer (seemed to be lagging a bit) and then after i put in my user name and password, the whole computer restored itself back to factory settings, however, my school documents and installed programs were still there. I couldn't find my music or photos. However, thank god for backing up my files every night or I could have been S.O.L My question is: why did this happen? How can I prevent this thing from happening again? Also: I just checked the amount of free space on my macbook, and I only have 28,27 GB of space free. What files can I delete on my computer that I wouldn't miss? Also, can I move my iPhoto library to my flash drive to save space?