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Delete all backups of all machines and reset time machine drive.

As you can see I just want to start over. There are some great discussions on deleting one backup at a time. I have 30 or so. I am changing mac and I would like to just reset time machine.

Please note the drive I have is external. So I can do it through disk utility by directly plugging in but I remember reading somewhere that it's not a good idea.

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Is the drive attached via USB or Ethernet/WiFi? In either case, what prevents you from just reformatting the drive and start from scratch? – patrix Apr 5 '13 at 4:03
It's connected via USB. Last time when I had trouble with reformatting, Time Machine wound't recognize the drive. That would be my next step, if you all think that's harmless. – Iam Apr 5 '13 at 5:08
It's connected via USB to Airport. I don't mind connecting the drive to my mac and just reformat it. – Iam Apr 5 '13 at 5:15
up vote 6 down vote accepted

Just wipe the drive clean using Disk Utility and then have Time Machine start it all over again. I'm not sure what kind of issues you are going to run into because I've done that probably 50 times in my life and never had an issue besides falling asleep while I wait for an entire Time Machine backup to finish.

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Disk Utility would be the best tool. But if you want to do it manually...

rm -rf doesn't work, even with sudo (fs denies permissions)

This is the only way to go:

sudo tmutil delete [path to machine name]


sudo tmutil delete /Volumes/BackupDisk/Backups.backupdb/oldmachine

Just use that command for every machine you want to delete. It will delete every backup for that machine.

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