My iMac gives an error when trying to backup, so I'm trying to erase the sparsebundle and start over. Every time I try, i get an error saying "The operation cannot be completed because the item 'bands' is in use." Any ideas on what "bands" is and how I can erase the TC? Is there a way to restore to factory settings instead of trying to erase the sparsebundles? (plural because I back up both my MB and iMac on it.