Had my iMac 2009 21.5" hard drive replaced a few days ago, from a 500GB to a 1TB. This was done by an authorized Apple repair dealer. I have been trying to run backups through Time Capsule but it seems to be getting hung up at one stage or another. Why is my Time Capsule backup getting stuck on "preparing backup" or "cleaning old backups?" The new hard drive has caused a huge positive difference in performance, which is suffering as the Time Capsule and backups get "hung."

1 Answer 1


Run tmutil status for a much clearer idea of what's actually happening. Keep running the command and the NumberOfChangedItems should be changing if the backup is taking place. Until then, the command will inform you what's being processed.

  • here is what I am seeing for NumberOfChangedItems = 1850001.The iMac has been on all day and it is still "preparing for backup" or "cleaning up."
    – Sizzle
    Dec 20, 2015 at 3:42
  • Head for pondini.org for troubleshooting. Your iMac may need to start a fresh backup on your Time Capsule. You can rename your existing backup file on the Time Capsule (e.g. iMac2009.sparsebundle) to another name (e.g. iMac2009.sparsebundle.old) and start again from scratch. This will break any history of backups, but your old backups and history will remain in the old sparsebundle file. You can still browse your old backups using the "browse other backup disks" function in Time Machine. The pondini website contains all the guidance you need. Jan 17, 2016 at 0:01
  • There is no "NumberOfChangedItems", it's stuck on "Preparing for Backup" for hours. CPU for backupd at 53%
    – gman
    Oct 12, 2016 at 3:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .