A number of backup-related issues in macOS 15.2 Sequoia are currently impacting Apple’s Time Machine utility, along with third-party applications such as SuperDuper and CarbonCopyCloner.
Initially, the concerns appeared to be limited to bootable backups, but indications now suggest a broader issue or multiple bugs are affecting various Mac backup operations.
The Issue Originated with SuperDuper
The developer of SuperDuper, Shirt Pocket, once utilized its own framework to create bootable backups of Mac volumes until Apple enforced the use of its own replication functionality, tightening the access for third-party developers.
Following reports of failed bootable backups, SuperDuper investigated the situation and identified the bug as residing in Apple’s replicator code in macOS 15.2.
macOS 15.2 was rolled out recently, bringing an unexpected and quite severe issue — Apple has compromised the replicator function.
The error occurs towards the completion of the Data volume replication, seemingly while attempting to copy either the Preboot or Recovery data, which results in a Resource Busy error. Previously, this could be mitigated by keeping the system awake; however, this new bug leaves most systems without a viable workaround. It simply fails.
Since Apple has removed the capability for third-party developers (like us) to copy the OS and taken responsibility for this feature, it’s now incumbent upon them to maintain its functionality. Unfortunately, they have not succeeded in this regard with macOS 15.2, as it is their own code that is failing, meaning OS copying will remain inoperative until they address the flaw.
Synology has reported that similar issues are affecting bootable backups to their NAS systems as well.
Broader Issues in macOS 15 Sequoia Backup Functionality
CarbonCopyCloner has also encountered difficulties, typically able to support bootable backups, but users have noted that non-bootable Time Machine backups are failing too.
macOS 15.2 disrupts Time Machine backups; a friend of mine experienced the loss of their entire backup history due to this issue.
The problems seem to particularly affect Apple Silicon Macs.
We have contacted Apple for a statement and will provide updates upon receiving any information.
Via Daring Fireball. Image by Samsung Memory on Unsplash.
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