macOS Sequoia 15.3 Fixes SuperDuper Bootable Backups Bug - MacRumors
Skip to Content

macOS Sequoia 15.3 Fixes SuperDuper Bootable Backups Bug

by

Apple's latest macOS Sequoia 15.3 update appears to have resolved a bug that prevented popular backup utility SuperDuper from creating bootable backups, according to developer Dave Nanian.

superduper macos
The fix addresses an issue introduced in macOS 15.2 that caused SuperDuper to fail during the final stages of creating bootable backups due to a "Resource Busy" error when attempting to copy system preboot or recovery files.

Apple requires third-party apps to use Apple's own replication tools rather than directly copying the operating system. When these tools malfunctioned in macOS 15.2, it directly impacted SuperDuper's ability to create bootable backups.

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

However, Nanian cautions that while the specific replicator bug has been fixed, this doesn't guarantee that booting from backup copies will work in all situations. This is largely due to changes that Apple has made in macOS and recent Mac hardware in the name of enhanced security.

For example, Apple Silicon Macs require that the internal SSD remains functional for external booting to work, meaning a Mac with a failed internal drive won't boot from a SuperDuper backup, even if the backup itself is perfectly intact.

Popular Stories

apple silicon mac lineup 2024 feature purple

Apple to Overhaul Mac Lineup With 11 New Models

Wednesday July 22, 2026 8:13 am PDT by
Apple is preparing to refresh every Mac it sells over the next two years, according to Bloomberg's Mark Gurman. The plans come amid a Mac resurgence, with sales projected to climb for a third consecutive year, partly thanks to a growing following among users who lean on the machines for demanding, agent-based AI workloads. The wave of new Macs will begin this fall with a refreshed...
Read Full Article • 125 comments
iPhone 18 Pro and Pro Max Feature

'Apple Upgrade' Program Reportedly Launching Next Week

Tuesday July 21, 2026 8:30 am PDT by
Apple and Klarna are partnering on a new "Apple Upgrade" leasing program set to launch in the U.S. on Tuesday, July 28, according to Bloomberg's Mark Gurman. The program will allow you to finance most iPhone, iPad, Mac, and Apple Watch models, with a 24-month term for iPhones and Apple Watches and a 36-month term for iPads and Macs. Customers will be able to pay off the device early during...
Read Full Article • 212 comments
iPhone 18 Pro Deep Red Feature

iPhone 18 Pro Launching in Two Months With These 12 New Features

Tuesday July 21, 2026 6:22 am PDT by
It is now mid-July, and that means the iPhone 18 Pro and iPhone 18 Pro Max are now just two months away. The devices are expected to look similar to the iPhone 17 Pro and iPhone 17 Pro Max, but there will still be many year-over-year changes, with rumored features including a smaller Dynamic Island, 5G via satellite, and more. Apple is expected to unveil the iPhone 18 Pro, iPhone 18 Pro Max, ...
Read Full Article

Top Rated Comments

D
Daalseth
19 months ago
“Apple Silicon Macs require that the internal SSD remains functional for external booting to work, meaning a Mac with a failed internal drive won't boot ('https://eclecticlight.co/2021/01/14/m1-macs-radically-change-boot-and-recovery/') from a SuperDuper backup, even if the backup itself is perfectly intact.”

WTF? Then what’s the point of a bootable backup? So the internal drive fails I need to get a new MB, or more likely a whole new Mac? That is ridiculous.
Score: 16 Votes (Like | Disagree)
H
H2SO4
19 months ago

Apple locking down macOS is the direct result of users not caring about security and privacy yet expecting to be made whole when their bank accounts and credit cards are compromised. It helps but you can’t fix stupid.
Please provide evidence for that ridiculous assertion.
Score: 11 Votes (Like | Disagree)
M
Moka Akashiya
19 months ago
Yeah, prohibit booting from external SSD when internal one is dead is definitely about security, and nothing about buying new motherboard/mac from Apple. You know, there is so much data on your external SSD about internal one when you boot from another one, you can access everything just like that!
Score: 7 Votes (Like | Disagree)
Infinite Vortex Avatar
Infinite Vortex
19 months ago
I love SuperDuper! as an app but I stopped using it quite a number of years ago given Apple making it difficult.
Score: 7 Votes (Like | Disagree)
Blackstick Avatar
Blackstick
19 months ago
This was a wildly useful app in the fun old days where one could boot Macs from external volumes by holding the option key alone with a firewire drive. There's a lot less need for it today, between Time Machine and Backblaze for offsite cloud, it has been sufficient.

Time moves along. Lots of ignorant users coming in... is why Apple continues to lockdown macOS. Early 2000s was a more fun time for OSX because effectively, nobody used it. Different era today.
Score: 5 Votes (Like | Disagree)
L
Lounge vibes 05
19 months ago

If it happens to me, instant lawsuit. I use 2 backups anyway, carbon copy cloner and superduper. TM is junk and always has been junk
I think your lawsuit would get thrown out pretty quick lol
Score: 4 Votes (Like | Disagree)
Read All Comments