I know there is tmutil delete to delete single timemachine snapshots from a backup of another machine — but now I need to delete only one of the folders inside the backup.

On my old (and now dead) iMac TimeMachine backed-up the internal «Macintosh HD» and an external FireWire-Disk named «ONE» … now I have a MacBook Air and just need the latest backup of the internal HD («Macintosh HD»). That means I've already deleted all the previous full and incremental backups («snapshots») with tmutil delete … but now I need also to delete the backup of the other volume that has been saved in this backup to free up space on the TimeMachine-Disk for new backups.

So there are two folders inside the latest backup:

/Volumes/TM/Backups.backupdb/iMac/2013-03-24-111738/Macintosh\ HD

representing the two volumes «Macintosh HD» (internal HD) and «ONE» (FireWire Disk).

HOW can I delete the folder/volume «ONE» from this backup-dir?

… Finder does not work, sudo rm does not work, tmutil delete only works with full snapshots…


2 Answers 2


Time Machine backups are protected at the kernel level by the TMSafetyNet.kext extension. You'll need to run the bypass utility that is part of that extension's bundle to delete the backed up file. See the answer to this related question on AskDifferent.com for complete details on where to find the bypass utility and how to use it.

How can I delete a file marked as backup item?


sudo /System/Library/Extensions/TMSafetyNet.kext/Helpers/bypass rm -r /Volumes/*/Backups.backupdb/*/*/*/Volumes/One

In 10.7 and earlier bypass was in /System/Library/Extensions/TMSafetyNet.kext/Contents/MacOS/bypass.

Other related questions:

  • 1
    On Sierra the path seems to be /System/Library/Extensions/TMSafetyNet.kext/Contents/Helpers/bypass. Aug 31, 2017 at 20:25
  • Thanks, also had to unmount and mount the drive again to see the result. The folder was still appearing in Finder even though it had been deleted.
    – malhal
    Sep 4, 2017 at 22:26

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