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I have a 1TB WD My Passport external hard drive that I've been using for Time Machine backups. I recently had an issue with it where I can't save to it anymore because it was corrupted. The way to fix it is to reformat the drive completely so I'm trying to copy everything on the drive over to my cloud (BitCasa or Dropbox), reformat the drive and then move everything back.

I have my Music folder on the hard drive and I've been able to move that successfully. When I try to move the Time Machine backups it says:

The volume is the wrong format for a backup.

I know that hard drives have to be 'formatted' to the Mac in order to be used for Time Machine backups but is there a way to just move the backup files around so I can get them off the hard drive. Thanks for your help!

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@bookcasey - Thanks for the bounty to draw attention. Are you looking for specific options or clarification? I've weighed in why I think this is a bad idea - but without knowing how many backup intervals are on the drive and how full the TB is of backup files, it's hard to be sure that cloud isn't a viable option. – bmike Mar 13 '15 at 11:56
up vote 4 down vote accepted

If your drive is corrupted in any way you probably don't want to use it for backup purposes any more, unless the data is not of great value to you.

Apple does not allow an easy transfer from drive to drive regarding backups. I think this is due to the way TimeMachine works (As stated in this apple discussion thread)

Now how to do it anyways ? I would simply use command line power. If you're the admin of the computer, you can simply open Terminal and do something along this:

  • sudo -s
  • rsync -avhW --progress < Drag and drop external Hard Drive here >< Drag and Drop DropBox folder here >


  • mv < Drag and Drop backup folder here >< Drag and Drop DropBox folder here, ending with a "/">

sudo -s puts you in the super-admin position, so you have full access to the system

rsync will sync the content and you can stop and continue at any time. mv will move the whole thing at once.

You should be able to drag and drop any folder within the backup to any folder on you internal/other external drive. Only the "Machine.backup" folder is protected.

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Copying the entire drive is a really bad idea for several reasons. Copying it to the cloud is also a bad idea. Buying a new TB or larger drive is far cheaper, faster, and easier and would let you just start backing up and put the "corrupt" backup on the shelf until you're sure you don't need to recover any files from it.

Due to the hard links that are used to save space when a file isn't changed, your backup method will have to deal with these links to avoid increasing the data transfer and storage requirements (depending on how many backup intervals are stored - you could end up with Petabytes of data from a 500 GB store of data).

It's much, much better to just pick one or two intervals to back up or let a tool like BackupLoupe interpret for you which files changed at which point in the backup so you can intelligently copy the files you really need off the drive.

Again, if you have more than 1 GB of files, I would avoid DropBox and slower clouds and get a tool crafted for large transfers like Arq or Transmit and push your files to Amazon S3 or possibly Glacier if you have multiple terabytes or more to store but won't likely restore any or all of it once you've determined what's really of value in the backup drive.

In practice, anything that lets you store unlimited data in the cloud will take far too long to get there, so minimize what you send up or pay for reasonable speed for the time you'll need it in the cloud.

That being said, if you really need to store it all, use Disk Utility to create an image of the drive (which hopefully can be done - it might fail to comply depending on the corruption that is present) so that you only copy the actual space used and don't get the hard links expanded into multiple copies of each file. Once you have a dmg (or compressed dmg), you can upload that.

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There are three ways to handle corrupted Time Machine backup drives:

  1. (easiest) Forget about the backup. It's a backup - you are not losing anything. Just erase it and start again.

  2. Copy the final backup (or just the parts that are really important) to other media. This can be done in the Finder, and it requires about the same space as what is currently on your drive/folders now. Note that restoring is not necessary - you already have the latest "backup" on your computer's primary drive

  3. Copy the entire volume, as-is. unmount the Time Machine drive and use either Disk Utility or Carbon Copy Cloner to do a block-level copy to it's new home. You will require another local volume at least as large as the current Time Machine volume. If you want to store it somewhere else, you can use a disk image - it counts as a "volume".

Unfortunately, there is no step between 2 and 3. Time Machine backups are one or all - it's not possible to split it in half.

If you are still considering cloud storage, I would think again. Look at the cost (and time) involved vs. the $100 cost of a 1 terabyte external drive.

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I've never tried this, so it's a theory only -

Copy the backup to a sparse bundle disk image

  • Launch Disk Utility.
  • From the Toolbar, select 'New Image'
  • In the Create dialog, set

    • size to be sufficient to contain the entire backup you wish to create [it will start smaller & grow to that maximum size as you fill it.]
    • Format - Mac Extended (Journalled)
    • Partitions - no partition map
    • Image Format - sparse bundle disk image
  • Disk Utility will save the image file where you asked it, format & mount to the desktop.

If we're lucky, that will then allow you to copy...

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But then one might just copy the backup to the source volume and save a bunch of 50 GB internet traffic/time. If i understand the OP correctly he tries to copy the backup directly to his cloud share folder - probably because of missing space on the source volume. – klanomath Mar 11 '15 at 18:45
@klanomath - erk, my bad. I'd completely missed the 'internet transfer' part of the question. I guess I'll leave this answer here as an example of a writing rather than reading exercise & take my down votes like a man ;) Either that, or I'll just recommend a new HD - they're cheap these days ;) – Tetsujin Mar 11 '15 at 18:58

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