If there is one thing we learn from the world of Technology: Things Change.
In days past, we made a “bootable clone” backup to an external drive, which could be used to start up a(nother) Mac. Need a new battery in your laptop or had to send your Mac to Apple for repair? Software update gone bad and your computer won’t boot? No problem, just connect your bootable clone drive to another computer, choose it as the Startup Disk and get work done while your machine is out for service.
The concept of a bootable clone has, very sadly, gone the way of the Dodo. Starting in Mojave (MacOS 10.14) and continuing through newer operating systems: Catalina (10.15), Big Sur (MacOS 11.x) and now Monterey (MacOS 12.x), and with modern Macintosh hardware (including Macs with the “T2” fingerprint scanner/security chip and Macs with Apple silicon “M1” processors), Apple has made making and keeping a bootable clone unreliable.
Mike Bombich discusses the details in this excellent article:
As noted in the article above, Apple’s operating system is now “cryptographically signed” upon installation and this signing is only possible with an Apple-built software tool. This means the clever tools Carbon Copy Cloner uses to make a backup drive “bootable” no longer work.
So how does this change the situation where you’ve had an issue with your computer and need to get back up and running ASAP? Given the inability to create a bootable external drive, Apple is now forcing us to rely on their “Migration Assistant” (https://support.apple.com/en-us/HT204350) to restore data from a “data only” backup. Unfortunately this can take hours while your data restores, vs. the near-immediate uptime of restarting from a bootable clone.
In the event of a catastrophe on your Mac, the process of restoring will now look something like this:
Here is Apple’s Support article on the process: https://support.apple.com/en-us/HT204350
As you can see, this process can be quite time consuming (~3-6+ hours) vs. time it takes to boot from your external backup drive.
There is no “fix” for this situation. Apple has chosen to make Mac OS and the Mac hardware more secure (as required by customers and current security, virus, malware and ransomeware vulnerabilities). Security is a good thing; unfortunately it comes with an inconvenient price tag sometimes.
For now, there is nothing you need to change about your Carbon Copy Cloner backups. CCC will continue to make full backups of everything on your Mac and can be used in the future with Migration Assistant (your CCC backup is called a “Startup Disk” in Migration Assistant-speak) to copy your user account, data and settings to a new computer or an erased computer with a newly installed operating system. If you haven’t updated to Carbon Copy Cloner version 6 yet (provides important compatibility fixes for macOS Catalina, Big Sur and Monterey), I recommend doing so. Choose “Check for Updates…” from the Carbon Copy Cloner menu. The update is only $20.