It’s Time to Move On from Bootable Backups

[ace (Adam Engst)]

In my article about macOS 15.3, I wrote:

@ace

Although the macOS 15.3 release notes don’t mention any bug fixes, Apple reportedly resolved the Apple Software Restore bug that prevented SuperDuper, Carbon Copy Cloner, and ChronoSync from creating bootable backups (see “It’s Time to Move On from Bootable Backups,” 23 December 2024). I’ve confirmed that SuperDuper can once again complete a bootable backup, and I assume the others can as well. That said, while I could select my backup drive in the macOS startup options screen, when my M1 MacBook Air restarted, it booted from the internal drive and displayed a kernel panic dialog. When I consulted ChatGPT and Claude about the panic log, they indicated it was related to a missing library. So perhaps Apple Software Restore isn’t fully functional yet.

Since then, I have confirmed that this is indeed a bug in Apple Software Restore that predates macOS 15.2. The problem is that asr sometimes fails to recreate a cache. Installing macOS over the backup “fixes” the cache. The problem is not universal, but the practical upshot is that if you consider a bootable backup essential to your strategy, it’s essential to test that it can actually boot your Mac.