Carbon Copy Cloner with Big Sur - which option to choose?

I always start with the "legacy bootable" option that now must erase the target volume.

But you can start with data-only clone and just install macOS on top of it to make it bootable later.

But be aware that the "legacy bootable" clone might not be bootable anymore if you do a data-only clone to it:

This does not always happen but if the source volume's macOS has been updated beyond a certain point, then the target volume no longer boots. CCC support suspected that the data volume might have some files related to booting. Recent Big Sur updates were OK in this respect but after 11.6.1 update it was necessary to either a) apply the full Big Sur installer to the non-bootable target to make it bootable again or b) boot the target and update it before doing a data-only clone to it. 11.6.1 updated also Mac mini 2018 firmware but I don't know if that always relates to this booting issue.

growler62000 wrote:

which option to choose?

It depends on what you want to accomplish.

I use both methods:

1 - A bootable system clone so I have a full replica of my system drive in the event I need either a) an emergency bootable copy of my system or b) to restore my system in full. Note that you should create a new bootable clone after each macOS update/upgrade in order to keep your bootable clone aligned with your updated system. In my case I only create a new bootable clone after updating my system and verifying that all is working as it should. I don't do it each time I install a new app.

2 - Data. I have automated CCC to backup various data folders daily to external drives. This way I have actual copies of my data files, not files buried inside TM that I could only get to via TM. And if you only want/need to backup your data, this is a whole lot faster than doing an entire system clone.

growler62000 wrote:

I have CCC (v.5.1.28) Set to run every day b4 I get up.

Since my recent upgrade from Catalina to Big Sur, as mentioned, I chose “Bootable System Clone using Apple’s proprietary APFS replicator.”

So I think this means I am creating a bootable clone every day & this s/b aligned with my updated system.

To make a bootable clone with Big Sur you need to choose the "Legacy" option by right-clicking or control-clicking on the destination option in CCC which pops up a context menu with the "Legacy" option. If you don't select the "Legacy" option, then you are only creating a non-bootable copy of the data. At least this is how I make a bootable Big Sur clone with version 5.x of CCC (I haven't tried v6 yet). To restore the clone to another drive you do the same thing again (i.e. choosing the "Legacy" option for the destination drive).

FYI, I've also cloned the Big Sur boot drive to a .dmg file using the same method which when restored to a drive will make the restored drive bootable. I am able to do this since I keep a bootable macOS external drive around when I'm repairing Macs so I can diagnose and backup multiple Macs if necessary.

Have used CCC for years and when using Intel based on Big Sur - use the Legacy Bootable Option. Then on separate drive - CCC Data backup.

Do the same on M1 units too.

> So I think this means I am creating a bootable clone every day & this s/b aligned with my updated system.

With my setup doing a 500GB bootable clone (Mac mini 2018 half-full 1TB SSD to a SATA SSD) takes about 25 min while a data-only clone usually takes only 30s - 2 min (or slightly longer depending how many large files or large VMs have changed. It is possible to exclude VMs from the CCC clones but I have not done that).

So I usually do data-only clones.

After macOS update a bootable clone is a good idea because a data-only clone might then make the backup unbootable if the source and target macOS differ too much (in my experience that is impossible to tell in advance. Big Sur 11.6 to 11.6.1 did this but a few earlier Big Sur updates did not. CCC support suspects that some files on the data-volume are also needed for successful booting). Another alternative is to boot the clone and update its macOS to the same level as the source, or apply the full macOS installer to the clone. In my setup all those options take about 30 minutes.

I would certainly opt for the bootable clone.

In the event of an issue with your system drive, this lets you start up using the clone in no time.

I have CCC to make bootable clones and also I have used it for data only. Both work to restore your data as required like when you first set up a new mac and migrate your info to the new Mac you can use either CCC drive. I have found with M1 macs booting is not as easy as with Intel Macs. I also use TM which works just as well to get your data back but it is always good to have redundant backups. When making a bootable drive using CCC and with the M1 Mac you need to boot from recovery unless you install the full OS on the CCC clone then it will show up in your startup pane in preference.i

Once you have made the bootable backup using CCC legacy system, you could in the future boot from it and software update it, from the Software Update pane, though I haven't tried that yet.

As I understand it, the data volume on this bootable backup will be updated as frequently as you have it programmed (task for copying the volume).

I have done it successfully, and like you was disappointed that bootable backups stopped being automatic.

But, for a variety of reasons, I think CCC is terrific and probably one of the best software programs out there. They are limited, unfortunately, by Apple's constraints.

I use CCC, but not to create bootable clones nor backup my startup volumes.

The CCC website has extensive details of what it is capable of and how it works. The blog there has more information on the technical details.

I did a test the other day with Monterey and the old version of CCC (5.1.28); I got a warning that v. 6 was necessary for this OS version and that my version was not "qualified". I wanted to see if it would work, so I opted not to upgrade CCC for the moment and just tried it. And, surprisingly enough, it did: a simple one click process with the old version and it copied whatever necessary and the result was bootable. I tested it. Mind you - it worked for me; don't know if it would work for everyone.

I just keep a bootable USB installer available.

It does take a few minutes to install, but not that big of a deal for me.

BTW, I keep 2 CCC backups on separate drives, 1 bootable and one not bootable