My macbook refused to back up today, stating that the identity of the time machine backup that it has been using for several months has changed identity. It then proceeded to backup the ENTIRE computer again to a new sparsebundle named the exact same thing but with a 1 after it. I was able to connect to and explore the original backup by pointing time machine to it, but when it backed up next it made the new sparsebundle again. What gives? How can i force the computer to use the old backup again?