SuperDuper! app icon amidst hard drives and a Mac keyboard. The developer of SuperDuper! says what they think is a bug in macOS Sequoia 15.2 has inadvertently broken how the app can create bootable backups — however, it may not be accidental at all. It's some years since Apple took steps to at least make it harder for people to start up their Macs using external drives. That was a privacy issue, a security issue, and a bit of a pain for anyone who remembers Mac drives failing.
Now according to developer Dave Nanian, Apple has gone further, maybe unintentionally. Nanian is the developer of backup app SuperDuper! and says that since macOS Sequoia 15.2 has changed a feature called the Replicator, his app has been unable to create a bootable backup.
"macOS 15.2 was released a few days ago, with a surprise. A terrible, awful surprise," he wrote in a blog post. "Apple broke the replicator. Towards the end of replicating the Data volume, seemingly when it's about to copy either Preboot or Recovery, it fails with a Resource Busy error.".
What this means is that at the last moment, a backup that is meant to create a bootable copy of a user's macOS system, will fail. "Since Apple took away the ability for 3rd parties (eg, us) to copy the OS, and took on the responsibility themselves, it's been up to them to ensure this functionality continues to work," continues Nanian. "And in that, they've failed in macOs 15.2.".
