Big Sur / Super Duper issue

I know that Super Duper has not yet been updated to create a bootable backup, but I assume it can still do some sort of basic backup.

I was trying to do that today and got a message saying the partition on an external drive I was trying to copy too needed to be in APFS format (I had it as Mac Journaled). So I formated it to APFS and tried to run a back up. Well, the only thing that happen was the timer elapseb on super duper kept going up, but nothing happened. Gave up after 50 minutes.

Tried restarting the Mac, but every time I open Super Duper now, it says my Macintosh HD isn’t mounted! If I close that warning, I can still select the Macintosh HD from the dropdown menu. But, as before, nothing actually gets copied.

So I looked in disk utility to see what it said was mounted or not and, frankly, I don’t get it. Here is what I see:

Apple SSD AP0512M Media - option to mount it is grayed out.
…Container disk1 - this one has an option to unmount, so I guess it is mounted now.
…Macintosh HD - this is gray but there is a button to “mount” it - which doesn’t seem to do anything!
…com.aple.os.update-55… - this has an unmount option so I guess it is mounted.

Finally, with the same indentation as Macintosh HD, there is “Macintosh HD - Data” - this also has the unmount button.

So how does this new system work and why can’t I mount Macintosh HD?

I would think, if it wasn’t mounted, I wouldn’t be able to boot the computer!

Before posting above, I did some searching, but didn’t find much useful.

I have since search some more and while much of it doesn’t have the clear statements I’d like to see, it at least seems that the Macintosh HD isn’t supposed to show up as “Mounted”.

Don’t know why, previous to me changing the external drive to APFS, superduper never gave any warning on my automatic scheduled updates. In fact, each day it would say the “last backup” was the day before. But it seems it never actually backed it up at all with new stuff since I was using Mojave.

But if anyone knows more about this, I’d be interested.

Take a look at:

This might be useful too:

And this:

I assume, from the preponderence of info, that it supposed to be listed “unmounted”. And I know superduper is not yet able to make a bootable copy. But what I can’t find anything about is whether supersuper is supposed to say it can’t find it (even though it is listed in the dropdown options) or not.

Big Sur is different than prior OSs. Major difference is that the system volume is signed. It cannot be updated, just replaced. Carbon Copy Cloner (CCC) does have an approach that works.

Create the bootable backup. (creates an APFS container and some volumes, one of which is Data)
Then create a backup task that updates just the Data volume because the system volume cannot be incrementally updated, just replaced.

If you make a change to the OS (security update or version update) on your local hard disk, it is not reflected on the CCC backup. To update the system on the backup drive, change to start up on the backup drive, update the system, and then restart on the local drive.

I have used CCC for years, and it has never failed me. I have used in two ways: straight replacement of the entire drive when installing a larger drive in my Mac; and pulling data and apps from a bootable drive (the backup drive) when using Apple’s recovery mode.

I’ve considered Carbon Copy Cloner, but would prefer not to have to get a second app - hoping SuperDuper comes up with something soon. I did check to see if SuperDuper gives an option to just copy Macintosh HD data, but it isn’t listed separately.

I assume data that actually matters on it is on my time machine backup as well as Backblaze. And some of the stuff I assume is normally saved there are some of the things I’ve moved to an external drive - notably my itunes stuff. Still, would be nice to have a bootable copy. Even if the boot copy doesn’t have the latest OS, that wouldn’t be a big deal.

I periodically look for a superduper update, but haven’t seen a thing or even anything to give me any idea if they think they are close to one. If they just said, “No, we won’t be able to do it”, I’d move on.

Some info for you on Super Duper and Big Sur compatibility:

Thanks! I’ll look more at this later today. But I was really surprised to find out that M1 Macs apparently have no way to even be booted from an external drive! I don’t like that.

One reason is because of the problem of having icloud stuff also stored on the Mac - I definitely want that so I’m not dependent on the cloud working. But from what I’ve read, Apple doesn’t allow the Mac storage of icloud stuff to be stored on an external drive like I can with iTunes music, movies, etc.

So what would be the purpose of getting 1 or 2 TB of icloud storage if the internal Mac drive could only hold 256 or 512 GB???


I don’t mean to be rude, but after six years of waiting on this product to be released, it seems that reading what is supposed to be a forum devoted to TextBlade, and finding lengthy discussions of software and hardware that has zero to do with the TextBlade is like rubbing salt into the wound!


Well, there are some very sharp people here who can provide useful info on other computer related issues so, since nothing else is happening, I figure it just makes sense to take advantage of what they know.

I don’t think it would be “better” if there was nothing at all. Or if the only thing to see were posts saying they want it to be released, over and over again.

Besides, we’ve had people complain about treggers providing real world experiences too, all with the reasoning that it rubs salt into the wound too.


Took me awhile to get around to making the change to the old SuperDuper version, but I just finished copying the internal drive.

For those who don’t know, you can no longer make a bootable copy because able divides up the main drive into two sections - one which apparently only changes when you update the OS. So even though it normally shows an one big drive, it isn’t.

So by going back to the older SuperDuper, it lets just the data portion of the internal drive show up and you can back that up. The bootable backup came in handy for me once when I had screwed up my internal drine, but this will do well enough. Seems to have worked okay.

One thing I’m not clear on though. On the main drive, Finder shows 4 folders:


But on the backup of that drive, it has those same 4 PLUS one called “boot” with 75 files which are all Greek to me. Takes about 270 MB so no big deal. Just wonder why it is there but doesn’t show on the internal drive. Maybe it is invisible on the main drive? But I unhid the folders and while 14 more showed up, none were named “boot”.

Anyway, thanks for the link to the solution.

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No worries. Glad it helped!

Found something interesting. I previously saw something about how you couldn’t boot an M1 Mac from an external drive. This bothered me for two reasons. One wa that I had an episode in the past where I screwed up my internal drive and, using Super Duper, simply made a direct copy from an identical bootable copy on an external drive back to the internal drive.

With the new structure of Big Sur, I’m not sure if there is any way to do that even with what I learned today, but maybe, with some adjustments.

But my other concern was that if you can’t boot from an external drive, an idea I had wouldn’t work.

You see, a big internal drive costs so much from Apple. Plus, as I understand it, if you keep a duplicate of your icloud stuff also on your computer (which I do), then what good does it do to have 2 TB of icloud space if your internal drive is only 512 GB? My idea was to maybe boot from an external SSD, so still pretty fast, but that SSD would be much bigger. Since the computer would be storing the icloud stuff on the boot volumn, I’d have enough space. Since I use a Mac Mini and don’t plan on ever buying another laptop, I wouldn’t even need a bootable internal drive (though I’d probably have it do that too).

Anyway, seems there is a way to boot from an external drive:

One thing about it really puzzles me as it says, after setting it up, when you switch back to booting from the internal drive, you should unmount the external drive. I don’t understand why that should be necessary.

Assuming all this does work well, I still have many things to evaluate to decide what to do in the future and answers to questions I have.

For example, suppose I have both the internal and external drive as bootable. We can back up the Data portion of a Big Sur drive, but not the operating portion.

I’m not sure, but it seems like I could back up the Data portion of the internal drive to the Data portion of the external bootable drive - and boot from the external drive and see no difference.

But I’m not sure. I believe the OS portion of the drive is something I can’t change, other than updating to a new OS version. But I don’t know if Apple makes changes to it internally as you make chances on the data portion. If it does change, then maybe my approach won’t work.

dbk, some info for you.
If all you are looking to do is protect your apps and data, then just backing up the Data volume of an APFS container is really sufficient. You can go to the Mac recovery mode to reinstall the OS and select the option to install the data that is on the external drive, and you will be back in operation. It will take longer than just booting from the external drive, but you will be back in operation.

The need to unmount is no big deal. Background – Unmount shuts down only one volume and keeps the other volumes mounted and drive connected. Eject gives the option to unmount all volumes and shut down the drive. When ejecting my APFS backup drive, the system asks if I want to Eject all drives, even though only one shows up on the desktop. It appears that the only the system volume is unmounted during the restart.

With the current Apple ASR utility, the only way to “back up” the operating system on an external drive while having started up from the internal drive is to recreate the entire backup drive - along with the Data volume.
You really don’t need to regularly update the system volume anyway, as you would just boot to an older version of the OS. And, you can update the OS on the bootable backup drive by first starting up from the external drive and then applying the updates.

Hope this helps

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I still get confused on details. Certainly I can get by just backing up the data portion, but I like the idea of being able to boot from an external drive:

  1. It can let you get right back to work if the internal drive fails.

  2. Apparently the internal SSD can’t be replaced (don’t know if Apple can do it to fix a bad one). And even if it can be, what happens when Apple declares a given computer “obsolete”? For example, I have the first iPad Mini. I think it could use a new battery. But I don’t think Apple will deal with it now so I don’t know what to do.

  3. And I’m still trying to consider the possibly advantage of always booting from an external drive (since I’d use a Mac Mini, this doesn’t cause problems that I know of in normal use, unlike if it was a laptop). Which would let me have a bigger, but cheaper, external SSD so I could have 2 TB iCloud storage which would also be saved on the external boot drive. But it wouldn’t fit on a 512 gb internal drive! Just an idea for now, but worth considering.

I realize that part of the M1 advantage is how everything is integrated and an external SSD would slow down the system, but I suspect it would still be pretty darn fast. And would extend the life of an old model when buying something new (using the old one as a server or something).

But I don’t know what the non-data portion does in everyday use (does it change at all) and that could affect things when backing up.

If, once the macOS is installed, the non-data portion doesn’t change at all, then it seems to me that I could install it on a backup drive. Once installed, that backup drive would have both the data and non-data portion. Then just keep updating the data portion and still be able to boot from it if needed if the other portion doesn’t have changes made during normal usage.

I realize it is easy to unmount a drive. What I don’t understand is why it would be necessary. Maybe it was not, but wasn’t worded clearly. But if it is, I’d like to understand why.

I feel that my idea for a bootable backup would work, but I don’t KNOW it would work. As with many things I research, it is hard to find someone who deals with the questions I have clearly. Not blaming anyone for that. I don’t say things well sometimes either. But it is frustrating.

Your third from the end paragraph is probably the most important one for you. It will definitely work.

If you really want to boot up and work from an external drive with no slowdown, you need to purchase a Thunderbolt external drive. Only way to keep up the speed of an internal drive. Only takes $$.

Yeah, and if I’ve read correctly, it needs to be thunderbolt connection to boot an M1 anyway.

I know that, sooner or later, I’ll go that route. Don’t need to worry about it for awhile since no reason to upgrade what I have plus, might as well wait for M2 - just hope Apple offers the Mini with an M2 chip!