Carbon Copy Cloner is a backup tool that copies your entire Mac hard drive to an external drive

Carbon Copy Cloner (often called CCC) is a program for Mac computers that makes a complete copy of your hard drive — everything on it, in the exact same structure — onto an external drive or another Mac. Unlike most backup programs that store files in a compressed archive you can't directly access, CCC creates what's called a bootable clone: a copy you can actually start your Mac from if your main drive fails or gets corrupted.

The program is made by Bombich Software and costs around $40 for a permanent license, though you can try it free for 30 days. It runs on Intel and Apple Silicon Macs running macOS 10.5 and later. The main reason people use it is speed and simplicity — if your Mac stops working, you can plug in the external drive, restart your computer, and keep working immediately without waiting for a restore process.

Key Takeaways

  • Carbon Copy Cloner creates an exact, bootable copy of your Mac's hard drive that you can start your computer from if the original drive fails.
  • Unlike cloud backup services, a clone lives on a physical external drive you control, so you don't depend on internet speed or a company's servers.
  • The program runs on a schedule you set, so you can have it clone your drive automatically each week or each day without doing it manually.
  • A clone is not a replacement for other backups — it protects against drive failure but not against accidental deletion, ransomware, or theft of the external drive itself.

How a clone differs from other backup methods

Most backup programs — like iCloud, Backblaze, or Time Machine — store your files in a format that requires the backup program itself to restore them. If you need a file back, you open the backup program, find the file, and restore it. A clone is different: it's a direct copy of your drive that your Mac can boot from and run as if it were the original.

This matters most when your main drive fails completely. With Time Machine or iCloud, you'd have to wait while the restore process copies everything back, which can take hours. With a clone on an external drive, you plug it in, hold down the power button while starting your Mac, and select the external drive as your startup disk. You're working again in minutes, not hours.

The trade-off is that a clone takes up as much space as your entire drive — if your Mac has a 500 GB drive that's 80% full, your clone will be about 400 GB. Cloud backups compress files and let you store more in less space. A clone also doesn't protect against accidental deletion the way Time Machine does — if you delete a file and then run a clone, that deletion gets copied too.

What Carbon Copy Cloner actually copies

CCC copies everything: your operating system, all your programs, your documents, photos, email, browser history, settings, and system files. It preserves the exact folder structure and file permissions, so when you boot from the clone, everything works the same way it did on the original drive.

You can set CCC to exclude certain folders if you want — for example, you might not want to clone your Downloads folder or your Trash, since those are usually temporary. You can also tell it to skip certain file types or to exclude files larger than a certain size. Most people clone everything and let the program handle the details.

One thing CCC does not do is encrypt the clone. If someone steals your external drive, they can plug it into their own Mac and see all your files. If you're cloning sensitive information, you should encrypt the external drive itself using macOS's built-in FileVault encryption before you start cloning to it.

Setting up automatic clones on a schedule

After you install CCC and connect an external drive, you tell the program which drive to clone and where to clone it to. Then you can set a schedule — daily, weekly, or monthly — and CCC will run the clone automatically at that time, as long as the external drive is connected and your Mac is awake.

Most people set CCC to run weekly, usually overnight or early morning when they're not using the Mac. Each time it runs, it only copies files that have changed since the last clone, so after the first full clone, each update takes much less time. If you clone weekly and your drive fails on a Tuesday, your clone will be at most a week out of date.

You can also run a clone manually whenever you want — before a major software update, before traveling, or before you take your Mac to a repair shop. CCC will show you how long the clone will take before it starts, so you know whether you have time to wait or should schedule it for later.

When a clone is useful and when it isn't

A clone is most useful if you rely on your Mac for work and can't afford downtime. If your drive fails, a clone gets you back to work in minutes instead of hours. It's also useful if you're upgrading to a new Mac — you can clone your old drive to an external drive, then clone from that external drive to your new Mac, and everything transfers over including all your settings and programs.

A clone is less useful if you mainly use cloud services like Google Drive, Microsoft 365, or iCloud. Those sync to the cloud anyway, so you don't lose data if your drive fails — you just log in on a new Mac and your files are there. A clone also doesn't protect you if you accidentally delete a file and don't notice for weeks. Time Machine keeps hourly backups for 24 hours and daily backups for a month, so you can go back and recover a deleted file. A clone only keeps the current state.

A clone also doesn't protect against ransomware or theft. If malware encrypts your files, it encrypts both your main drive and your clone. If someone steals your external drive, they have a complete copy of everything on your Mac. For those risks, you need a separate backup — either cloud backup or an encrypted external drive stored in a different location.

Carbon Copy Cloner compared to built-in Mac backup

macOS includes a free backup tool called Time Machine that comes with every Mac. Time Machine backs up your entire drive to an external drive or network storage, and you can restore individual files or your whole drive from it. The main differences from CCC are speed and convenience.

Time Machine is slower to restore from because it has to copy files back one at a time. A clone is faster because your Mac can just boot directly from it. Time Machine keeps multiple versions of your files going back weeks or months, so you can recover a file you deleted long ago. A clone only keeps the current state. Time Machine is free; CCC costs $40.

Most people use both: Time Machine for everyday file recovery and protection against accidental deletion, and a clone for fast recovery if the drive fails completely. You can set Time Machine to back up to one external drive and CCC to clone to a different external drive, so you have two separate copies of your data.

Frequently Asked Questions

Can I use a clone to move to a new Mac?

Yes. Clone your old Mac to an external drive, connect that drive to your new Mac, and use CCC to clone from the external drive to your new Mac's internal drive. Everything transfers over — programs, files, settings, and user accounts. This is faster than using Migration Assistant for most people.

What happens if I clone while my Mac is running?

CCC can clone while you're using your Mac, but the clone won't include files that are currently open or being written to. For the most reliable clone, quit all programs and let CCC run while your Mac is idle. You can also schedule clones to run at night when you're not using it.

Do I need a special external drive for cloning?

No. Any external drive that's larger than your Mac's internal drive will work — USB, Thunderbolt, or FireWire. The drive should be formatted as Mac OS Extended or APFS. CCC can format the drive for you when you first set it up.

Can I clone to a network drive or cloud storage?

CCC can clone to a network drive (like a NAS or shared Mac), but not to cloud services like iCloud Drive or Google Drive. Network clones are slower than USB drives but useful if you want the clone stored in a different physical location.

What if my clone drive gets full?

CCC will stop and alert you. You'll need to delete the old clone or use a larger external drive. Some people keep two external drives and alternate cloning to each one, so they always have a recent backup even if one drive fills up.