Cloning mac or Create Image of Macbook / IMac.

What version(s) of macOS is(are) your Macs running?

There are, at least, two third-party cloning apps: Carbon Copy Cloner, and SuperDuper! However, starting with macOS Big Sur (11.0), the operating system resides on a cryptographically sealed "Signed System Volume" that can only be copied by an Apple-proprietary utility. AFAIK, neither of these two apps can perform this function.

Using CCC or SD to clone a bootable macOS boot drive for an Intel Mac may still work fine (I haven't tried it for a couple of years since Monterey), but you are likely to encounter issues making a bootable clone on an M-series Mac since there is a new concept of "Ownership" & "secure tokens" which are not well understood.

FYI, here is the note being referenced by one of the other contributors where the CCC developers explain about the issues of bootable clones these days and the best option moving forward. These are great developers, so you should take their insight here very seriously.

https://bombich.com/en/kb/ccc/6/cloning-macos-system-volumes-apple-software-restore

HWTech wrote:

Using CCC or SD to clone a bootable macOS boot drive for an Intel Mac may still work fine (I haven't tried it for a couple of years since Monterey), but you are likely to encounter issues making a bootable clone on an M-series Mac since there is a new concept of "Ownership" & "secure tokens" which are not well understood.

There are some articles on the Website for "The Eclectic Light Company" about this, e.g.,

The Eclectic Light Company – How external bootable disks work with Apple silicon Macs

The Eclectic Light Company – Create an external bootable disk for Apple silicon and Intel Macs

The Eclectic Light Company – Ownership means two different things in Macs: how to tell them apart

The Eclectic Light Company – Thunderbolt ports aren’t all the same

The second article claims that "All Macs with Apple silicon chips can start up from a bootable external disk without reducing their boot security using Startup Security Utility" if you follow certain steps.

Some of those are non-obvious, like making sure that you connect the external drive to one of the Mac's non-DFU ports. (Many Mac users would not even know that certain ports were DFU ports - much less which they were.)

Apple has a Support article

How to identify the DFU port on Mac - Apple Support

but the Eclectic Light people say "Beware when reading that support article, as it isn’t internally consistent: for instance, it shows the DFU port as being that on the left of the left side of a MacBook Pro, but states in the text that on a MacBook Pro 14-inch 2024 with an M4 chip, the DFU port is that on the right of the left side instead."

I have made several bootable drives (clones) of my Mac M series units. First boot into recovery and install the OS on the external. Then when the system reboots migrate from your internal to the external. Then it is a clone and boots without issue. However, when you do any update to the internal in the future you also need to do that to your external to keep all in sync or may run into issues. The only issue for anyone wanting to use the external as the main drive is it will not support any AI feature. If using an Intel Mac then the process is much easier as you can use CCC to make a bootable drive directly but I still use the M series method to be safe.

If you have an Intel Mac or MacBook you can successfully clone your Mac to a bootable external SSD by following this user tip: Using Carbon Copy Cloner to Make a Bootable Clone of an Intel Mac - Apple Community. I've sucessfully cloned systems up to and including Ventura, macOS 13.

Tesserax wrote:

What version(s) of macOS is(are) your Macs running?

There are, at least, two third-party cloning apps: Carbon Copy Cloner, and SuperDuper! However, starting with macOS Big Sur (11.0), the operating system resides on a cryptographically sealed "Signed System Volume" that can only be copied by an Apple-proprietary utility. AFAIK, neither of these two apps can perform this function.

These days, for either of those utilities to make a bootable "clone" backup, they must use that Apple utility, or have you install macOS over the backup, to create a valid "Signed System Volume".

There was a time when the Apple utility had not been implemented (or was not working correctly), and the only way to make a bootable "clone" back was to run the backup utility and then re-install macOS in place. You can probably find articles describing this on the Bombich (Carbon Copy Cloner) site.

The Carbon Copy Cloner vendors seem to think the handwriting is on the wall for making bootable backups, so default CCC settings now are just to clone data and not to make the backup bootable in and of itself.

Note that if you are backing up an APFS drive where APFS performed lazy file copying (two different files share space on disk, because the contents of the shared space are not yet different), the backup may be significantly larger than the original.

tbirdvet wrote:

I have made several bootable drives (clones) of my Mac M series units. First boot into recovery and install the OS on the external. Then when the system reboots migrate from your internal to the external. Then it is a clone and boots without issue. However, when you do any update to the internal in the future you also need to do that to your external to keep all in sync or may run into issues. The only issue for anyone wanting to use the external as the main drive is it will not support any AI feature. If using an Intel Mac then the process is much easier as you can use CCC to make a bootable drive directly but I still use the M series method to be safe.

Thanks for the information. I especially did not know about the section I put into bold in this quote.

I've been wanting to experiment with external boot drives on M-series Macs, but just have not had the time or enough motivation.