But I’ve never seen such a warning with SD, and it has always created reliable bootable backups.
On Monday, after upgrading to SD 4.01, I did a complete backup of my M4 Mac Mini running mac OS 15.7.8 to a Samsung external SSD. When I restarted the mini from that backup, it was somewhat slow, but definitely usable. I am planning to FINALLY “move” to the latest version of Tahoe on both of my Macs soon. I am confident all will be fine, including SD bootable backups.
As has been said earlier, the lack of a warning in SD is a matter of policy, not technical capability. Both CCC and SD use ASR to clone a fresh copy of the SSV. SD has no magic sauce to do this better than CCC.
You have been lucky. Bootable clones have been flaky with Apple Silicon, especially early on. I have tested bootable clones at various times with CCC and SD and had problems with both, depending on what Apple were doing at the time. Because of this CCC decided as a matter of policy to promote restoring a clone of the Data volume using Migration Assistant as the prime method, (which is also how a TM restore is done) while SD continued with the bootable clone.
The CCC position and justication is explained in this link I posted earlier.
I should add that I think both programs are excellent and well supported. Over the years I have used each as my main tool. Since Apple Silicon CCC has added capabilities to position itself as a complete alternative to Time Machine (including for example ability to create local snapshots on the boot volume like TM). This probably makes CCC appear as a more complex tool than SD.
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Well…there is some magic sauce in there, actually…for example, we provide actual progress info during a replication, and do follow-up operations on systems that benefit from it.
But, certainly: there’s a reason I say “Apple willing” for boot: there can be problems. But that was, quite literally, always the case, even before the SSV. Various kernel extensions, programs with low-level requirements, etc, could interfere with external boot…it didn’t have to be this. But I don’t think it’s a matter of being “lucky”. It really does work most of the time, assuming a reasonable external (preferably SSD).
Even though I obviously could, I purposefully did not turn SuperDuper into Time Machine. Time Machine does a lot more than just create snapshots: it uses internal APIs to create deltas on the backup drive that are much different than what it did before, and far more efficient than just leaving a bunch of snapshot checkpoints on the backup drive (and requiring more UI to manage it).
I basically feel “let Time Machine do what it does, because it does it well” (especially these days). It doesn’t need to be replaced…it needs to be supplemented, which is what SuperDuper does.
(Note that I do copy from a snapshot for obvious reasons, and I do create a Time Machine managed snapshot on the destination during a copy, purely to give a way to recover from an accidental copy to an unintentionally selected drive. That snapshot ages out according to Time Machine, deleted and the system’s own rules.)
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Thanks Dave. I haven’t done it for a while but I suspect the external bootability problems have reduced since the early days, when it really seemed like a lottery for a while. Maybe Mike Bombich would not have made his policy change if it was as it is now.
PS I was referring to snapshots on the source, like TM does. So backups get made even when backup drive is not connected. Maybe SD can do this as well now.
Re: snapshots like Time Machine…sure, but that’s something Time Machine does already.
Time Machine has improved a lot…I see no need to reinvent that particular wheel.
The other advantage of using Time Machine as well: when Apple needs to intervene, they will often refuse to deal with 3rd party backups…which they shouldn’t, but that doesn’t mean they don’t. And since there’s nothing different on a SD backup than what would be on any drive copy… 
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It’s not a matter of luck. I make a sincere and concerted effort to ALWAYS take care of my machines by keeping them “lean, mean, and clean”. And that is clearly the case, given that I have never had any issues with bootable backups made with SD (thanks David!). And I’m willing to bet there are numerous others who have the same experience.
Thanks David for verifying what I stated. I have read many horror stories of folks not taking care of their machines, and it has led to issues, problems, etc. That is why I make a concerted effort to take care of each Mac I own (and have owned), and my issues have been very, very few. For a couple of those, restoring from an SD bootable backup resolved the problem.
I truly appreciate your efforts, tenacity, and support. We have had numerous discussions, and you have always been there. Again, I just feel so fortunate that there are still individuals like you around (although tehy are few and far between).
Thanks again!
Howard Oakley (and others) have discussed this. A likely cause of failure is creating and/or booting the clone using the DFU port.
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I am well aware of avoiding the DFU port for my backups. But that is not the only reason why folks would not be successful with SD and bootable backups. It is not a matter of luck (seems like a lot of folks think that way!) that I have had no issues. It’s a matter (like with other things, and cars are a perfect example) of taking care of what you own. I firmly believe that my concerted efforts over the years have been a definite reason why I hardly have any issues. And it’s the same with our cars, appliances, etc. If one is lazy and does not keep after such maintenance’/cleaning activities, they are asking for trouble. I make sure to avoid issues as much as possible.
As somebody who is interested in how people think and behave, Fooled By Randomness is one of my favorite books. It’s a short polemic that explores how human beings can mistake luck for skill, especially in financial markets and high-stakes careers.
I am sure your good practices are a factor, but in the early days of silicon (long before Apple announced the DFU port issue) bootability of externals was very flaky, even with lean clean test volumes. For a while Thunderbolt connection was more successful than USB 3, and certainly SSD were more successful. The issues with Apple affecting bootability were genuine and led Mike Bombich to his change of policy.
It is interesting that in that period the DFU port requirement had not been revealed, so it may have been a factor in the flakiness. OTOH when the DFU port became a thing I deliberately tested bootable clones made on the wrong port and they worked!
I like the way CCC positions and handles the bootable copy functionality. When you select a backup disk, you’re given a choice (“Standard Backup” vs. bootable copy, and some other choices too) and some context around the choices. I never felt that the bootable copy function was unsupported or otherwise inaccessible in CCC, it’s presented as an option right alongside the other options. Bombich’s reasoning seems pretty straightforward – if Apple is going to periodically break this functionality (which has happened repeatedly, I believe Nanian pointed this out in his blog too), is it reliable enough to suggest that people build their backup strategy around it? Troubleshooting a boot issue is the last thing I want to be dealing with if I’m trying to recover my Mac from a backup.
This whole discussion had me curious enough to test this on Golden Gate this afternoon. Both CCC and SuperDuper “successfully” created a bootable copy, but it doesn’t show up in the Startup Disk pane, nor in the Startup Manager when holding down Power on boot. Broken again? I put in a support request to Bombich about this and they said it’s an issue they just discovered: https://support.bombich.com/hc/articles/20686463881367-macOS-Specific-Issues-That-We-re-Tracking. They filed a bug report with Apple, and offered a workaround (that worked for me, too). Granted Golden Gate is still beta, maybe Apple will fix it before the fall. As far as I can tell, though, Bombich is still fully engaged and on top of the bootable copy business, they just aren’t happy enough with the reliability of it to tell people to base their backup strategies on it.
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I think I’m pretty clear that the fact that something will boot is nice, and a bonus, and useful, and not something that you’re “basing your backup strategy” around, David. There’s no need to mischaracterize my position here.
A question about V4 (If you’re still watching this thread) — in previous versions there was a single window that showed everything that was scheduled. I don’t see a way to do that with the new version. I have to click on a particular volume to see if it’s scheduled or not. I have several different volumes on different schedules. A single schedule window would sure simplify things for folks like me. Thanks!
If you search on a schedule term (eg “every day”, “weekend”) you should be able to get to the scheduled jobs pretty easily. They’re not in one window, no…but the jobs will be filtered.
Thanks for quick reply! That’s close, but the V3 schedule window sure was handy to check on status/schedule of everything at a glance and helped avoid overlapping schedules.
Ah, but you see, overlapping schedules don’t matter… you can schedule as many as you want, and overlap as much as you’d like.
I understand that, but a snapshot of everything that’s scheduled (and maybe mistakenly not scheduled) as in V3 sure is handy to keep track of what’s happening when. Don’t get me wrong, v4 is fantastic. I just get weary having to jump around looking at each volume. I like to keep my scheduled backups separate, probably harking back to golden olden days of slower processors and slower drives (with a touch of old dogs … new tricks…). Thanks for your gracious patience in this thread and for all you continue to do for us!
Let’s live with this for a while and see how you feel after you get used to it… 