Carbon Copy Cloner & Catalina

Backup and Cloning software has a lot to contend with in the upcoming Catalina OS. What about the HFS+ file system? How does it deal with the APFS Snapshot system? Carbon Copy Cloner by Mike Bombich is one of the best cloning and backup Apps in the Mac universe. It has been around for a long time, is super supported and is a very versatile cloning and backup App. With all the changes in the upcoming Mac OS Catalina, CCC has had to make changes too as will all backup cloning software. I wanted to list a few of the changes in CCC that jumped out at me.

CCC Catalina Changes

As previously mentioned there are significant changes in the Catalina OS. I am sure I will upgrade to it on my main workflow machine, but I recommend proceeding with caution, especially if you have some older, legacy Apps you need to keep using. Having said this, for most people CCC will just work as normal. They won’t have to change their backups because CCC is handling things under the hood:

CCC will make bootable backups of macOS Catalina startup volumes. For most people, that’s all you need to know, and you don’t have to make any changes to your current tasks to accommodate the upgrade. The logistics of booting macOS are a bit more complicated in macOS Catalina, but we’ve risen to the challenge, CCC supports it 100%, and nearly all of these complications are dealt with automatically.

CCC will take care of most issues automatically for most people. However, there are some things that affect me and may affect you:

HFS+ Is Dead

Apple has been moving away from the old HFS+ file format for quite some time. All things are moving toward APFS, that is just the future of Mac computing. From the CCC website:

Allow me to be the first to say it: stick a fork in it, HFS is done. HFS simply won’t work for making a backup of a Catalina system volume, so in the near future, we’re going to drop support for backing up macOS (Catalina and later) to HFS+ formatted volumes. We plan to make this as easy as possible for you, though, so don’t go out of your way to get ready for this. My goal is to make this transition as simple as possible for you and your backups.

This is important to me because a couple of my backups go to HFS+ drives. The fix for this looks pretty seamless though:

macOS Catalina requires APFS, it cannot be backed up to a volume formatted with Apple’s legacy HFS+ format. When cloning a macOS Catalina system volume, CCC will inform you of this requirement and request your permission to allow conversion of an HFS+ formatted destination to APFS. When you proceed with the task, CCC will automatically convert the destination to APFS (when possible). When you upgrade to macOS Catalina, any existing backup tasks that reference your startup disk and a non-APFS destination volume will be disabled and flagged for review. If any scheduled tasks are disabled in this manner, CCC will be opened automatically on startup and these concerns will be raised to your attention.

I definitely plan to report back on this process. Hopefully, it will just be a seamless conversion of the backup drive to APFS with no issues. If anyone can do this, Mike Bombich and CCC can.

System & Data Volumes

As previously mentioned, Catalina has a Read-Only System. Therefore, it makes a System and a Data Volume. The System Volume stays locked and you can access and change the Data Volume. CCC will handle this in its backup scheme:

CCC will automatically create System and Data volumes on the destination as required to support APFS volume groups.

When selecting an APFS volume group member as a source (i.e. your current startup disk), CCC will automatically copy the contents of both the System and Data volumes to the corresponding System and Data volumes on the destination. No special configuration is required for this, you will simply choose a single source and destination as you have in the past.

CCC has always been a smart backup cloning App and it is going to remain that way.

Restoring A Backup

The new APFS system is based on something called “Snapshots”. You can read more on that here. CCC will handle Snapshots like this:

CCC offers great flexibility for restoring from System and Data volume snapshots. For example, you can restore from a newer Data volume snapshot and an older System volume snapshot, allowing you to downgrade the System without losing newer data. However, care should be taken when restoring System and Data volume snapshots that are associated with different OS versions, we don’t yet know the implications of mixing these.

This may sound a bit confusing, but it really allows a great deal of versatility when Restoring items from a backup clone to your main Mac. 

I reiterate, any backup or cloning software will have to deal with these issues; HFS+, APFS Snapshots, Restoring Files and many others in the new Catalina way of doing things. I know CCC will be up to the task and I am sure many other backup Apps will be.


Before upgrading to Catalina, I highly recommend checking into your backup software to determine where they are on providing reliable backups and clones. No sense in installing a new OS if you cannot back it up.