Apple Silicon Macs Will Not Support Booting From External Disks In Future

As Apple is phasing out the creation and use of external disks, Mac devices using Apple Silicon will not be able to boot from external removable disks in the future. For some users, creating a bootable disk for their Mac can add additional security to prevent the primary disk on the Mac from being damaged or encountering other problems. But with Apple’s gradual transition to the Apple Silicon chip, this kind of backup technology that allows users to quickly restore operation will no longer be supported.

Mike Bombich, the founder of Bombich, the developer of the well-known software Carbon Copy Cloner (hereinafter referred to as CCC), wrote in a blog post on May 19 that the company will continue to provide bootable backups for Mac devices from Intel and Apple Silicon. As long as macOS supports this feature, it will continue to provide support.

However, with the introduction of Apple Silicon, the functionality of the Mac has changed, and the ability to use an external boot may be limited, partly because of Apple’s design decisions.

The first problem is macOS Big Sur, because Apple makes macOS reside in a “sealed signed system volume” plus, this can only be replicated by Apple software restore. While CCC has the ability to use the software reduction (ASR) program, but the tool is considered to be endless beauty, its failure “without any explanation”, and the “very single” manner.

The second obstacle is Apple Fabric, a storage system that uses encryption keys for each file. ASR didn’t work for several months, and it was not restored until the release of macOS 11.3. When cloning back to the original internal storage, the kernel panic also followed.

In December last year, Bombich said: “Many people in our Mac community can see that this is the direction of Apple’s development. Now we have finally confirmed it. Especially since the introduction of APFS, Apple has been moving towards locking macOS system files. Development has sacrificed some convenience to improve safety.”

A change was discovered in a product safety document in February. Bombich pointed out that it mentioned that the boot process of Apple Silicon Macs is always driven by a volume on the internal storage. The lightweight operating system on the volume evaluates the integrity of the boot assets and authenticates the operating system on the external device before booting from the volume.

He said: “In theory, this means that if the internal storage fails, the Apple Silicon computer will not start at all.” Apple’s internal experts “clearly confirmed” to Bombich that if the internal storage fails, you cannot boot the Apple Silicon Mac from the external boot drive.