I think that a distinction should be made between being able to boot from an external drive—which can be done on M1 macs.
And whether the regular clone backups which are useful to have, using 3rd party apps, need to be bootable, as a necessity.
The latter, I would have said yes to before. And I’d like the ability back eventually.
Apple is going through multiple transitions: HDD/Fusion to SSD (hopefully done now), APFS (and the various partition changes), M1 (and the various startup modes), affecting this particular feature.
Hopefully, when they’re done with all these whatsit transitions, I’ll be able to boot from USB-c drives that were cloned using 3rd party software (1st. party software, even better). Maybe even the old Target disk mode could come back. There’r already rumours about computer MagSafe coming back, so who knows?
Until then, I don’t even have a single Thunderbolt 2 or 3 or 4 accessory that is not an adapter, let alone a M1-bootable external drive.
I can not pretend to completely understand all of the ins and outs of the technology problems with bootable clones mentioned in the article and the replies here. However I do use bootable clones for reasons not often mentioned (in addition to the one where you need to travel with a clone and borrow or use a local Mac to continue work from home). I’m a stickler for backups for archival purposes: multiple copies of external archives, at least 2 different cloud services, and Time Machine, and an off-site local backup.
I experienced the death of a parent in December. She had worked with Macs since the Mac Plus days and the development of Pagemaker. She had thousands of archived files saved from various versions of both Pagemaker and Indesign, etc. These files are of historical value to both our company, her civic organizations, and family. The older the file, the earlier the version of the apps you will need to upgrade to newer file formats. The apps only convert old files created after a certain version. And the newer the system, the less you can install an old enough version of apps to enable conversion.
I cloned her computer (still on High Sierra) with the associated older versions of software so that I can continue to access her creations as far back as possible with what she was using. I want to be able to, over time, begin to select important files and either convert them to newer versions, newer programs, or at least make PDFs of them. It would be impossible this soon into life without them to know which are crucial enough to convert or access “right now” and doing them all could take another lifetime.
At times I also need to boot her computer to research old email, find obscure contacts and significant calendar events, find an old image in Photos that I don’t have, etc. Being able to preserve the state of a computer as of a certain date is quite useful to some of us. Is this a minority of cases. I’m sure. But for some of us this capability is a literally a “lifesaver.”
First of all, thanks for this great coverage. This is what makes Tidbits great: getting insight into surprises Apple tries to sneak in without consumers noticing, but which end up affecting us and leave us scratching our heads
This change increases security even more, but it also prevents all backup apps from creating bootable duplicates because they cannot sign the backed-up System volume.
Why can’t the backup software just make a clone of the cryptographically signed volume byte for byte? Is it hashed against some type of unique hardware identifier like a UUID that will be different, and therefore invalid, on the external drive?
Good question, and perhaps @glennf knows more. My suspicion is that yes, it’s tied to the Secure Enclave, if available, or to some other specific bit in hardware.
Secure boot begins in hardware and builds a chain of trust through software, where each step ensures that the next is functioning properly before handing over control.
You can install Big Sur on Macs without Secure Enclave, though, so there may be something else at work. At Howard Oakley’s excellent Eclectic Light site, he notes back in June 2020:
The only time you’re likely to come up against the SSV is when using bootable macOS volumes by cloning or from a macOS installer. Whatever you use to do that needs to preserve all the hashes and seal, or the volume won’t be bootable. All good cloning software should cope with this just fine.
However, that was before good cloning software tried to tackle the problem. So it may be that the way the SSV is created is died to drive-specific or APFS container-specific identifiers that cannot be simply duplicated or duplicated at all. A new Big Sur installation on an external, bootable drive apparently allows the creation of an SSV from scratch.
Glad you mentioned this site again. It prompted me to read it more closely.
Anyway, light reading there now reveals that
Failure of internal storage means failure of the whole Mac, which can’t then boot from an external disk
Not thrilled.
On one hand, I have at least twice booted from an external drive to continue working on a Mac with a busted internal drive. One was a busted Apple-standard 4200 or 5400RPM hard disk, and booting from an external 7200RPM drive sped the computer up). The other was a OWC 3rd party SSD.
On the other (smaller) hand, I haven’t had much experience with newer Apple soldered-SSDs. And I don’t think there’s many reports of iOS internal storage failing…
All this is getting off topic, but I had to correct my earlier post which said that M1 Macs could boot off external drives. They can, but, seemingly not if the internal drive cannot be read from.
Last word on topic: I agree with this article. And that clones are still useful even if not bootable.
Off topic:
So, over the years Apple may have selected a set of customers willing to buy increasingly unupgradeable desktop/laptops: from physically-difficult-to-replace drives (iMac), to soldered-on-drives-and-RAM. To now making the computer unusable if the irreplaceable internal storage dies.
I mentioned this in an earlier post on a different thread, that it is sad that these expensive computers, could potentially over time, be less useful compared to a Raspberry Pi.
A very nice article. Thank you. What I miss in the part of a modern backup strategy is how to mitigate against ramsonware. If your computer has been infected with ramsonware, it can take several days, up to several months before it get’s activated. Time Machine, Backblaze and daily clones are not going to save you because your backup is already corrupted. What would be a good strategy to mitigate against ramsonware? I’m thinking of weekly backups with some kind of Tower of Hanoi rotation, problem is you need at least 5 rotating clones and that is an awful lot of required disk space. Anybody a better solution? Or should I not worry about ransomware?
For an attack like this, there is no perfect solution. No matter how many weeks, months or years of archival system backups you make it is always possible that the point of infection is older than all of them.
If you find yourself in such a situation, then you probably can’t restore the entire system. Instead, you would need to cleanly reinstall the OS and your applications, and then restore only your documents from a backup created before the ransomware activated.
They can do it once and it works (an initial clone, only on Intel Macs), but after that, they can’t update the System volume. It has to be erased and the whole clone redone. They can only update the Data volume incrementally.
@glennf and I just had a long back-and-forth in Slack about how I misinterpreted some of the information scattered across the Carbon Copy Cloner blog and FAQ with regard to bootable duplicates in Big Sur. @bombich, does this sound right now?
You can use CCC to make a one-time full clone on an Intel-based Mac, making it bootable. However…
CCC won’t make incremental System volume updates on an Intel-based Mac because Apple’s asr utility requires a full erase and a re-clone of the System and Data volumes. That would be far slower than a normal incremental backup.
Since asr is not functional in Big Sur on M1-based Macs, CCC cannot currently create a bootable clone of an M1-based Mac. However…
You can make a CCC data-only backup bootable by manually installing Big Sur on it afterward.
Keeping macOS up to date on a bootable clone on either an Intel- or M1-based Mac requires occasionally booting into it and running Software Update.
Well, that’s not so bad, eh? The system volume doesn’t get updated much anyway, right? And when it does, even an incremental backup will have a lot to copy, making the need here to do a fresh, full backup not much worse.
I have to agree here. As much as I’m an Apple fan, this is one of those innovations I can’t embrace now. I have a system of backups that use a combination of SD! and Time Machine. It’s worked well for me over the years and saved me a couple of times. I’m not giving it up. Yes, that means I probably won’t be buying an M1 and upgrading to Big Sur in the near future. I regularly sing the praises of Apple’s products, but sometimes (and this is one of them them) I think they push the envelope too far and too hard. I buy Apple because I have work that I need to get done. I don’t want to spend a lot of time adjusting my workflow and my life to the newest innovation.
FWIW, something similar happened to me. My 2015 27" 5K iMac had internal 500GB SSD which failed last month after only 2+ years. I also experienced “occasional odd behavior” but tried to soldier on until it failed, relying on my backups… What I found out that is helpful maybe to you: 1) the failing drive affected quality of the backups (hiccups, blank data) resulting in almost useless accuracy of backups - had to go back thru my backups (Cloud and physical) to piecemeal verify and replace data/files lost; 2) the price of SSD’s are so much lower than I expected, that replacing my internal SSD with a 1TB SSD was hardly and issue. When SSD’s fail, it happens over time therefore (for me) it’s harder to calculate the extent of damage. I’d advise replacing sooner rather than later. Hope this helps prepare you…
I agree and having been burnt a couple of times by iCloud, I use it very very sparingly. I have long concluded that Apple has never really been on top of cloud. I have been using DropBox but it is now trying to be a Swiss army knife doing all sorts of things and has compromised its functionally.
I, for one, will be supremely disappointed and annoyed if Apple does not offer some way to sanction bootable backups. The whole point is to be able to do emergency work while you wait for a new drive to arrive, as well as for enough time to do the restore.
On a fixed income, I certainly can’t afford to have a spare blank drive waiting around “just in case.”
I don’t really think fixed income customers are any priority at all at Apple these days. For one, the company wants people to buy and buy again frequently, not use till dead. Stuff is not made to last forever (and I’m not talking hardware here). And secondly, the company is hell bent on selling people ‘services’. They need to spend more and more, not a fixed allotment every month. Hardware sales in their opinion have only little room to grow, their share price OTOH has to increase every single quarter. And that is how they want to make this happen. Your fixed budget is nowhere near compatible with that plan. In their defense, most tech companies these days seem to think similarly and only total world domination is viewed an acceptable definition of success. There’s a good chance they’ll eventually come around, especially considering international trade barriers and legal proceedings popping up everywhere, but you’re going to need to hold your fixed income breathe for another while I’m afraid.
I think there’s no question this is happening—the question is just when, and how many hoops people will have to jump through until it’s fully implemented. From the article:
In theory, Apple’s asr (Apple Software Restore) tool makes this possible, but it didn’t work at all until just before Big Sur was released, still has problems, and even now cannot make a bootable duplicate of an M1-based Mac boot drive. On the plus side, Apple has said it plans to fix asr , but who knows when, or how completely, that will happen.
