Using a CCC backup with a loaner Mac

This documentation is for an older version of CCC. You can find the latest version here.
Last updated on 2023年1月13日

Sometimes when you send your Mac off for a repair, you just can't go without "your computer" for the duration of the repair. In this article we'll offer some best practices on how to quickly get your data backed up and transferred to a loaner Mac, how to get the data back to your Mac when it returns from the shop, and how to quickly and securely remove your data from the loaner Mac.

Before you send your original Mac out for repair

CCC's default settings are designed to create a backup of your Mac that can be easily migrated to another Mac. Configure a CCC backup task to back up your startup disk to a locally-attached, APFS-formatted device. This Kbase article offers step-by-step guidance: Establishing an initial backup. Ideally, you already have a CCC backup. If you wait for your Mac to break before creating a backup, you might not have an opportunity to create one, or it may be logistically difficult (e.g. damaged display).

Before you accept the loaner Mac

Upgrading your data to a newer OS is usually uneventful. Downgrading your data, however, is virtually impossible, and is completely unsupported by Migration Assistant. If your current Mac is not on the latest OS, and if you specifically do not want to upgrade to a newer OS (e.g. when your Mac is returned), then you need to be very careful about what OS you migrate your data to. Before you accept a loaner Mac, verify that the OS installed on that Mac is the same as the OS that you're currently using (or newer, if you're willing to upgrade your Mac upon its return).

If you can't acquire a Mac that has the same OS as your current Mac, you should avoid migrating your data to that Mac. Instead, attach the backup disk to the loaner Mac and access your files directly from the backup. This is a less-ideal configuration because you lose some hardware redundancy when you work directly from the backup, but it's often less risk than dealing with the hassle of trying to downgrade your data from a newer OS.

When you get the loaner Mac

Prior to transferring data to the loaner Mac, we recommend that you enable FileVault on that Mac's startup disk. By enabling FileVault, your data is never placed onto the loaner Mac in an unencrypted form, and securely removing it from that Mac can be done in a matter of seconds.

Transfer data to the loaner Mac using the following steps:

  1. Boot the loaner Mac (from its own internal disk).
  2. If prompted in Setup Assistant, skip the option to migrate data.
  3. Proceed to create a new user account. Name it something temporary, like "utility".
  4. Once logged in, open System Settings > Privacy & Security and turn on FileVault.
  5. Attach your CCC backup disk to the loaner Mac.
  6. Go to System Settings > General > Transfer or Reset and click "Open Migration Assistant..."
  7. Proceed to migrate data from "a backup" – choose the CCC backup volume as the source.

While you're using the loaner Mac

Especially if you plan to use the loaner Mac for more than a day or so, we recommend that you establish a backup task that will back up any changes you make to your data while using the loaner Mac. This will also get you prepared for taking your data back to your original Mac when it gets back from the shop.

  1. Open CCC.
  2. When prompted, leave your other backup tasks suspended.
  3. Configure a new backup task to back up the current startup disk to your backup disk.
  4. Schedule the task to run at your preferred frequency.

Because all of your data is already on this backup, the task should go pretty quickly to update the changes that you're making on the loaner Mac.

When you get your original Mac back from the service center

  1. On the loaner Mac, quit all applications except for CCC.
  2. Run the CCC backup task one last time to get everything on the backup up to date.
  3. Detach the backup disk from the loaner Mac; now just leave the loaner Mac as it is – don't delete anything from it yet.
  4. Boot your original Mac (from its own internal disk).
  5. When prompted by Setup Assistant, accept the offer to migrate data from a backup. †
  6. Attach the CCC backup disk to your original Mac and select it as the source in Migration Assistant, the proceed as directed to migrate all of your data back to the original Mac.

† If your Mac was not returned from the service center with a clean installation of macOS, open System Settings > General > Transfer or Reset and click Erase All Content and Settings... prior to attaching your backup disk to the original Mac.

When the migration has completed

After migration is complete and you've logged in to your account on the original Mac, the very last step is to securely remove your data from the loaner Mac and return it in "clean install" condition.

  1. On the loaner Mac, open System Settings > General > Transfer or Reset.
  2. Click Erase All Content and Settings...
  3. Authenticate in the Erase Assistant, then click Continue to remove your data from the loaner Mac.

When that process has completed, the system should reboot to Setup Assistant. Because you had enabled FileVault on the startup disk before transferring data, all of your data was 100% securely removed from that system, pretty much instantly. You can now turn off that system and return it.