ISO Tips, Tricks, and Warnings to wipe Time Machine drives for repurposing?

I have an external hard drive (or two) that have old Time Machine backups. I’d like to wipe these drives to repurpose them for other uses. I have additional storage to be able to extract files from them before I erase them. I thought I would do this …

  • Mount the drive
  • Select the drive as the Time Machine volume to explore
  • Open the most recent view into the Time Machine vaults on the drive
  • Restore the most recent folders to an internal temporary volume
  • Wipe the TM drive to repurpose it
  • ZIP the extracted folders and store them on an external drive as representative archives

For example, I have a Time Machine drive labeled as being from my 15" MBP. I would mount the drive, open it in TM, go to the Documents folder at the last backup date, and drag sub-folders such as Documents/Anthologies, Documents/Code, Documents/GTD … to my temporary internal volume.

I’m purposely not going to bother hunting down folder versions before the most recent stored on the TM drive. Mantra – If it hadn’t been stored in some other way by the last backup, it wasn’t worth the effort to keep earlier versions. My only reason to extract the most recent versions of key folders is a self-assurance that, sometime in the not so distant future when I do a pruning across all my archives, I may not be lamenting the loss of a certain file that I knew existed in a certain folder in the period I was last using the computer. IOW, even as I am not hunting backwards in time beyond the most recent TM backup, I am not yet willing to simply wipe it all and (blissfully) move on.

Before I start, I’d wondered if anyone had any tips, tricks, or warnings to share about my plans.


Since the old time machine drive has no newer files than the computer, and you want to make an archive of what you have, why not just copy the folders of interest to a new drive or even just clone to a new drive.

I just don’t see any purpose of copying from the most recent time machine backup on an old time machine drive.

I believe you are saying what I am saying. I would copy out the folders of interest from the most recent backup folder made on the drive. IOW, I would not go to the folder for the first backup, I would go to the folder for the last backup made before the drive was taken out of service.

I am not sure what you mean by “clone” to a new drive?


A quick and dirty approach is to get an external drive equal or larger than the internal drive and just copy everything on the internal to the external. Then you are sure you have everything. This is trivially easy to do with a program like SuperDuper! or CarbonCopyCloner.

I need to transfer files OFF of an external drive to wipe the external drive. The files on the external drive are in TimeMachine volumes. I would use my internal drive only as a temporary location, and I would capture folders only form the most recent backup in the TM volume. So the process is

  • copy TM2015 MBP/Documents/Code @ backup date 2022-11-20 → internal drive
  • copy TM2015 MBP/Documents/GTD @ backup date 2022-11-20 → internal drive
  • ZIP all above into on internal drive
  • erase TM2015 MBP
  • copy → external drive
  • trash all files that are created on the internal drive from above process

Now that I understand, I believe that I am not needing a clone.