A bug in macOS Sequoia 15.2 has reportedly broken third-party backup apps. The developer of SuperDuper! says a bug in the recent macOS update has broken how the app creates bootable backups.
Dave Nanian, the developer of backup app SuperDuper! 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.”
Any backup that is meant to create a bootable copy of a user’s macOS system, will fail at the last moment.
“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.”
“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,” he says.
The alleged bug has to do specifically with creating a backup that can then be used to start up their Mac from. The bug does not affect backing up data to external drives.
Time Machine is so far reportedly working correctly and there haven’t been any reports of the issue affecting other backup apps.
Other backup apps may not be affected due to their backing away from offering bootable backups. SuperDuper! competitor Carbon Copy Cloner claims only to make a “best effort” to create a bootable backup for specific use cases like migrating between Intel Macs.
“We can’t fix it…. Apple has to do so,” says Nanian. “It’s unfortunate this is happening during this period, since Apple rarely releases updates between now and New Year’s.”
