Carbon Copy Cloner
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I want to back up multiple Macs or source volumes to the same hard drive

This documentation is for an older version of CCC. You can find the latest version here.
Last updated on March 22, 2017

Backing up multiple volumes or multiple Macs to a single hard drive can be a messy proposition. If you back up each source volume to the same destination volume without some pre-planning, data from each source volume will be merged in a heap on the backup volume. Additionally, your tasks will archive or delete each other's backed up content. Carbon Copy Cloner can solve this problem! We lay out a few different scenarios and solutions below.

"I want a bootable backup for each Mac on the same hard drive"

Creating a bootable backup requires that you provide a dedicated backup volume for each Mac that you want to back up. If you want to maintain each bootable backup on the same hard drive, you simply create a partition for each computer that you want to back up using the Disk Utility application.

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"I want to back up my startup disk and a data volume to the same backup disk"

If you prefer not to partition your backup volume as described above, you can use two CCC backup tasks to manage these backups. The first task will back up your startup disk directly to the backup volume for a bootable backup, the second task will back up your data volume to a subfolder on the backup volume. Thanks to CCC's SafetyNet feature, the two backup tasks will coexist peacefully.

  1. Configure a CCC task to back up your startup disk to the backup volume. Choose your startup disk from the Source selector and choose the backup volume from the Destination selector.
  2. Verify that the SafetyNet feature is "On". [Note: If you have Advanced Settings enabled, be sure that the Protect root-level items option is checked.]
  3. Schedule the task, if desired, or choose "Save" from Carbon Copy Cloner's File menu. You can run this task immediately or let it run on schedule later.
  4. Click the "New Task" button in CCC's toolbar.
  5. Choose your data volume from CCC's Source selector.
  6. In the Finder, create a new folder at the root level of the destination volume to store your data volume's backup. Finder may prompt you to authenticate if you ran the first task already, and that's OK.
  7. Drag the new folder from the Finder onto CCC's Destination selector.
  8. Schedule the task, if desired, or choose "Save" from Carbon Copy Cloner's File menu. Again, you can run this task immediately or let it run on schedule later.

CCC's SafetyNet will prevent the first task from erasing the content that you're backing up to a subfolder on that same destination volume.

"I want to back up multiple data volumes (no OS files) to the same backup disk"

The easiest way to back up multiple data-only volumes to the same backup disk is to create a folder on the backup disk for each volume you want to back up. Then you'll configure a task for each source volume that you want to back up, setting the destination to that disk's dedicated folder on the backup disk.

  1. Click the New Task button in CCC's toolbar.
  2. Choose your data volume from CCC's Source selector.
  3. Choose Choose a folder... from the Destination selector
  4. Select your destination volume in the sidebar
  5. Click the New Folder button to create a new folder at the root level of the destination to store your data volume's backup, then select that folder as the destination.
  6. Schedule the task, if desired, or choose Save from Carbon Copy Cloner's File menu. You can run this task immediately or let it run on schedule later.
  7. Repeat the steps above for other source volumes, creating a new folder for each at the root level of the destination volume.

"My backup volume isn't formatted as HFS+ because I also use it to back up my PC"

There are a couple options for backing up to a volume that isn't formatted as HFS+. If you're only backing up user data — files that reside in your home folder, for example, then you can back up directly to the backup volume. Non-HFS+ volumes often don't support all of the filesystem metadata that is associated with files on an HFS+ formatted volume, but that's generally OK if you aren't backing up system files or files that belong to another user account on your computer.

If you are backing up system files to a non-HFS+ formatted volume, you can back up to a disk image. A disk image is a single file residing on your hard drive that contains the entire contents of another hard drive (except for the free space). When you want to access the contents of that filesystem, you double-click on the disk image to mount the disk image as if it were an external drive attached to the machine. Carbon Copy Cloner leverages disk images to provide you the flexibility of storing several complete backups on a single shared external hard drive. To back up to a disk image:

  1. Choose your source volume from the Source selector.
  2. Select "New disk image..." from the Destination selector.
  3. Unless you're making an archival backup of your data, choose the option to create a read/write "sparse bundle disk image" file
  4. Specify the location where you want to save the disk image file.
  5. When you run the backup task, CCC will create a disk image on the backup volume, back up the specified data, then unmount the disk image when the task is complete.

Note: While disk images themselves are not bootable, you can mount them and restore their content to a physical hard drive to produce a copy of the original volume. If the original volume was bootable, the restored volume should be able to boot the original Mac as well.

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