If Time Machine gets disrupted for any reason during a backup (ie. hard drive unplugged, power failure) it seems to get stuck. Occasionally it gets stuck for reasons only known to Leopard. Its a known bug on the Apple discussion boards. What has worked for me is the following:1. ensure hard drive is powered on and connected to computer2. turn off time machine3. go to your backup volume, backups.backupd, "your computer name", and then select and trash "In Progress" or "Latest" (it will be the last one in your backup folder listing)4. turn Time Machine back on5. either wait for the next backup cycle, or what I do to be sure things are working right is force an immediate backup (control-click on TimeMachine, select "backup now").
