One or more backup bugs in macOS 15.2 Sequoia is affecting Apple’s own Time Machine utility, as well as third-party apps SuperDuper and CarbonCopyCloner.
Initially the problem appeared to affect bootable backups only, but it now appears that it is either more general than this, or there is more than one bug affecting Mac backups …
Things started with SuperDuper
SuperDuper developer Shirt Pocket originally used its own code to create bootable backups of Mac volumes, before Apple locked things down so that developers had to use the company’s own replicator functionality.
After SuperDuper bootable backups began failing, the company investigated and found that the bug was in Apple’s replicator code in macOS 15.2.
macOS 15.2 was released a few days ago, with a surprise. A terrible, awful surprise. 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. In the past, Resource Busy could be worked around by ensuring the system was kept awake. But this new bug means, on most systems, there’s no fix. It just fails.
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. And in that, they’ve failed in macOS 15.2. Because this is their code, and we’re forced to rely on it to copy the OS, OS copying will not work until they fix it.
Synology said that the same issue is impacting bootable backups to its NAS systems.
Wider macOS 15 Sequoia backup bug(s)
CarbonCopyCloner was also affected, which again normally supports bootable backups, but then users reported that (non-bootable) Time Machine backups were also failing.
MacOS 15.2 breaks Time Machine backups. A friend had his entire backup history blown away by Time Machine.
The issue appears to be specific to Apple Silicon Macs.
We’ve reached out to Apple for comment, and will update with any response.
Via Daring Fireball. Photo by Samsung Memory on Unsplash.
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