The SuperDuper Bootable Backups bug has been fixed in macOS Sequoia 15.3.

According to developer Dave Nanian, an issue that stopped the well-known backup program SuperDuper from producing bootable backups appears to have been fixed in Apple's most recent macOS Sequoia 15.3 release.



A "Resource Busy" error occurred when SuperDuper tried to copy system preboot or recovery files, causing it to fail during the last stages of producing bootable backups. This issue was fixed in macOS 15.2.

Instead of directly cloning the operating system, Apple mandates that third-party software utilise its own replication tools. SuperDuper's capacity to produce bootable backups was directly hampered when these utilities failed in macOS 15.2.

Nanian posted on his Shirt Pocket Watch blog that "macOS 15.3 is now out, and with it, a fix for the broken replicator." "As such, macOS copying will work again with 'Erase, then copy' backups."


Although the particular replication bug has been resolved, Nanian warns that this does not ensure that booting from backup copies will function in every scenario. This is mostly because of the security-related modifications Apple made to macOS and new Mac hardware.

For instance, a Mac with a failing internal drive won't boot from a SuperDuper backup, even if the backup is in great condition, because Apple Silicon Macs require the internal SSD to remain functional for external booting to function.