Update: Dave Nanian, the developer of SuperDuper, has confirmed that Apple has resolved the issue in macOS 15.3.
Backup issues in macOS 15.2 Sequoia are affecting Apple’s Time Machine as well as third-party applications like SuperDuper and CarbonCopyCloner. Initially, it seemed that these problems were limited to bootable backups, but it appears either the situation is more widespread or multiple bugs are disrupting Mac backups.
Troubles Originated with SuperDuper
Initially, Shirt Pocket, the developer behind SuperDuper, utilized its own code to create bootable backups for Mac volumes until Apple restricted developers to using its replicator functionality.
Following the failure of SuperDuper bootable backups, the company conducted an investigation and identified that the issue was within Apple’s replicator code in macOS 15.2.
macOS 15.2 was launched a few days ago, and it came with an unexpected, unfortunate surprise—it broke the replicator.
Near the end of replicating the Data volume, right before copying Preboot or Recovery, an error occurs with a Resource Busy message. Previously, this could be circumvented by ensuring the system stayed awake. However, this new bug means that, on most systems, there’s no workaround, and it simply fails.
Since Apple removed the capability for third parties to copy the OS and has taken responsibility for it, it falls on them to maintain this functionality. Unfortunately, they have not succeeded with macOS 15.2. We rely on their code to copy the OS, so OS copying will be non-functional until they implement a fix.
Synology also reported that this issue affects bootable backups to its NAS devices.
Broader macOS 15 Sequoia Backup Issues
CarbonCopyCloner users also faced problems, as the tool that typically supports bootable backups also exhibited failures for non-bootable Time Machine backups.
macOS 15.2 disrupts Time Machine backups. A friend lost his entire backup history due to Time Machine issues.
The problems seem to be particularly relevant to Apple Silicon Macs.
We have reached out to Apple for a comment and will provide updates based on their response.
Via Daring Fireball. Photo by Samsung Memory on Unsplash.
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