I think it happened at the same time. I keep getting a message that the backup to time machine failed because "he backup disk image /Volumes/Untitled/Davids MacBook Pro.sparsebundle is already in use." I'm using a western digital external harddrive attached to an airport extreme by usb. When I open time machine preferences, the backup disk is shown as "unititled". I don't know how to find out whether it is in use (the lights on the WD drive are not flashing). Any ideas?