After cloning my internal drive to an external drive using Carbon Copy Cloner and booting from the external drive once (then booting from my internal drive again), Time Machine thinks that every single file on my computer has changed. How can I fix this?

Details: I recently installed Carbon Copy Cloner and made a clone of my drive to an external. The external is partitioned into two parts - one for the clone, and one for Time Machine. The Time Machine partition predates the clone partition. Last night I ran a first clone and backed up everything, so I left my computer open. Time Machine ran a couple backups overnight and everything was fine. This morning I booted from the external disk to make sure the clone was working. Once I booted from my internal drive again and opened up Time Machine to run a backup, it took a very long time to calculate then finally decided to attempt to back up my entire hard drive again. I've tried ejecting the clone volume (even though it is excluded from backup) and of course a restart, to no avail.

I am running a late-2011 15" MacBook Pro with Mavericks.

  • Did you mount the internal drive when booting from the external clone? If so, you probably changed a few indicators Time Machine uses to determine what was changed. – Daniel Beck Dec 2 '13 at 11:04
  • @DanielBeck I only looked through my files and opened some apps. Does the internal drive mount automatically? – Julien Clancy Dec 2 '13 at 11:18
  • I guess OSX did automount your internal drive while you booted from your clone. This way everything your mac saw was on a different drive and changed your backup according to that. When you started your Original installation then - it rewrites every file again. This can be a big problem if your TM drive is pretty full, with big files every duplicate adds up. The solution may be: only use CCC backups when they are needed (and even then - override the drive you've taken the snapshot from) or unplug your Time Machine drive when booting the backup. – Gotschi Dec 13 '13 at 18:07
  • @Gotschi so, the only thing to do now is to erase my Time Machine drive and start over if I don't want duplicates of everything? – Julien Clancy Dec 15 '13 at 19:39
  • I would not suggest to erase a drive! Especially a TM drive. Time Machine saves edits of saved files (so you can see what you have written in a document over the days). Maybe you need this sort of backed up files some time. I just don't think you'll find an easy way to make it work like it did before CCC. – Gotschi Dec 16 '13 at 10:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.