Carbon Copy Cloner restore limitations

Is this restriction always true? Because I recently created a bootable backup of an M2 MacBook Pro (running Ventura 13.6.2), by doing a full asr clone (via SuperDuper!). I had to run the Ventura installer on top of it to get past a bug in asr, but the result was bootable with my user account intact.

(I am absolutely not trying to claim SD is more capable than CCC. I’m just saying, I think the asr copy works without using the migration assistant.)

And by the way, Mike: you can update your website’s info about the custom icon bug for external drives. I can set custom icons now on Monterey and Ventura. The key is to set it while booted to the external drive; then it will be displayed when not booted from that drive. Sometimes you have to click the icon on the desktop before the Finder will refresh it, though.

You could certainly have the exact same result from a bootable copy made with CCC. CCC still offers “make a bootable copy of the system” functionality (we have all along).

This is just one of many reasons, however, that we don’t recommend incorporating bootability into a backup strategy, there’s constant hassle involved with it. If you’re going to have to install macOS anyway, you might as well just cut the ASR/bootability part out. And in many cases (especially on Apple Silicon), there’s a faster way to strip the system down to a “clean install”: System Settings > General > Transfer or Reset > Erase All Content and Settings. That takes just a fraction of the time of the traditional nuke & pave, and it avoids a lot of procedural crap in Recovery Mode (mostly specific to Apple Silicon).


“Migration Assistant pulls the apps right off of the [CCC] backup…”
This good to know. I see that the CCC help page that you link to above has detailed advice about using Migration Assistant with a CCC backup.
Thank you for joining the discussion.

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It’s been several months since we tried (memory of it might not be 100%) but this definitely didn’t work for us (it’s detailed on here somewhere and I may have spoken to you about it at the time). We were trying to migrate a Wordpress server (with a custom Apache/PHP/MySQL install) to a new machine and Migration Assistant simply ignored it all. We had a 110GB site on the CCC backup and MA simply refused to move it.

I can’t remember whether we tried a Restore in CCC - I think we followed the suggestion to use Migration Assistant - but I’d be surprised if we didn’t when MA failed. It provided many hours of grief and the end result was off-boarding the entire mess to a hosting provider which provided a ‘one click’ install. Amazing this could be provided by a third party host - across platforms - but not by Apple or one of the long standing apps for an Apple to Apple copy.

In the past we would have booted the new machine from a clone, cloned to the new machine and rebooted. A new server instal typically took a few minutes with virtually no down time. I’m a massive fan of CCC and have used it for many, many years, I think we have about 20 licenses. Apple’s decision to remove one of the most useful capacities of the platform drives me insane.

I still have the old machine here, I might look for a spare machine and see if I can get CCC to Restore.

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Does this have implications for restores from CCC backups to NAS volumes over SMB? In particular, it seems to imply that it’s impossible to do a full-disk clean restore in this case (since they aren’t using APFS).

Yes – direct-to-NAS backups aren’t suitable for use with Migration Assistant. We offer two methods for restoring data from a NAS:

Restoring from a backup on a NAS or network share
Restoring a home folder from a backup on a NAS to a clean install of macOS

But if you want a backup that’s usable for “full Mac recovery”, we recommend using locally-attached storage.


It seems not just NAS backups. I was in the office today to update a user with a new machine. She has an old Mac Mini, 250GB. I want to move her to a newer machine, also 250GB. Despite having 50GB of free space on the donor machine, and the new machine being a clean install, Migration Assistant failed with a message akin to “Not enough room for migration”.

Migration Assistant’s only consistent feature is its capacity to fail miserably.

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I remember working with you on a “migrate our Mojave Wordpress Server (Mac Mini 2018 Intel) to a new M2 Ventura machine” scenario back in March 2023. This is definitely a case where it starts to get into the weeds – the new OS and new CPU platform situation has implications for whether/how that older server software would work. IIRC, all of the macOS-builtin web software was just not present on the new OS, which meant that new (and different) software had to be installed to support the website. Servers are a more challenging scenario. Our recommendation is to always start with a “Standard Backup” (a bootable has no relevance in this scenario) and to use Migration Assistant to migrate the data. Occasionally there are cases where MA doesn’t transfer something (perhaps for valid reasons), and whenever that occurs, that’s when we’d recommend performing additional restore activity with CCC. In this case, for example, I did recommend exactly that – find where the data lives, then perform a folder-to-folder restore with CCC. But obviously in this case it was still way more complicated than simply restoring the data because the server services were just not present on the new OS.


People often tend to throw Migration Assistant under the bus when stuff like this happens. Apple has culpability here, for sure, but Migration Assistant is not to blame. I’d love to share some additional insight, but it would take three different paths depending on context. What was the source for the Migration?

  • Original Mac in Target Disk Mode (Intel)
  • Original Mac in Shared Disk Mode (Apple Silicon)
  • Time Machine backup of the original Mac
  • Other backup of original Mac (what software?)

Is this an Apple Silicon thing?

My 2018 Mac mini, running Sonoma still has an Apple-provided Apache web server. Apple disables it as a part of major system upgrades (Catalina to Big Sur, then Ventura and later to Sonoma), but it was pretty trivial (one apachectl command) to re-enable it each time. They also reset the Apache configuration files, but they preserved my files via the “Relocated Files” mechanism. It was similarly easy to run a “diff” to compare my files against theirs and put back my changes.

It took a few minutes, but I agree that this is something that has to be done manually and I assume Migration Assistant won’t touch this.

When I used Migration Assistant to migrate from a 2011 mini running Sierra to a 2018 mini running Catalina, I had to manually re-apply my Apache configuration (the software was present, but disabled and in a default configuration), and there was a glitch migrating my home directory, but (much to my surprise), all of my custom software installed to /usr/local came through fine and just worked (because my original Intel builds were already 64-bit). The MacPorts packages also came through OK, although I did update/rebuild them just to be safe.

Thanks Mike. I don’t want to hark too much on my particular issues as I have another machine I can give her with a 500GB drive. It’s the frustration of dealing with tools which should work which don’t.

For the record, I made a CCC clone of the donor machine (Mojave/APFS) and attached by Thunderbolt to the replacement machine (Mojave HFS+). I booted the donor to target disk mode, ran MA and it failed (not enough space). I then rebooted the donor machine, ran MA and chose “To another Mac” and tried the process again - Mac to Mac - with same error. I didn’t have time to try anything else as I had to do the entire procedure while she was on her lunch break. I’d like to try a CCC restore but would need to do it over the weekend.

I appreciate going from APFS to HFS+ might present issues but I doubt it’s a situation which wouldn’t have been considered possible. Our experience with APFS hasn’t been good and we’re actively avoiding it where possible.

APFS to HFS+ will almost definitely have issues, I would generally not expect this to be possible in every case. APFS offers several space-saving techniques that aren’t supported on HFS+. If the source has sparse files or files duplicated via clonefile(), for example, then those files will consume more space on an HFS+ destination.