Clean Install or Upgrade/Migration for new Monterey iMac

I’d very much appreciate expert advice before diving in on this project of moving from a Big Sur iMac to a new Monterey iMac. Since this is my wife’s computer, this needs to go very well. :wink: LOL :wink: LOL

With great success I’ve always followed Joe Kissell and Take Control’s advice but now I’m tempted to wander from his usual primary recommendation of only do a Clean Install if other doesn’t work.

Background. My wife’s iMac continued to be problematic. If would freeze or restart almost daily. On our second or third trip to The Apple Store, Apple replaced the logic board, wiped it clean and assured us that all was well. However, her iMac continues almost daily to report “Restarted due to problems.” The only improvement is that it does not totally freeze.

So rather than invest more time with a return trip to The Apple Store, I purchased her a new iMac which just arrived. Now I’m debating a Clean Install vs. Migration/Upgrade. She is running Big Sur on her current now old iMac (2017 model).

I’d like to do a Clean Install given these current and past problems but this oldie doesn’t really know what could go wrong and what he is biting off. Everything is backed up once or twice per many years of following advice from Adam and Joe. :slight_smile:

All of her docs are either on Dropbox or iCloud in the case of photos or Google in the case of Gmail. That’s in addition to daily CCC backups to an external drive.

Any reactions or recommendations from Tidbits-Talk experts is greatly appreciated.

Thank you very much.

FWIW, her computer is very vanilla, at least in my opinion.
Non-Apple applications are:
Microsoft 365 (v16)
BusyCal and BusyContacts

And then she uses:
OS X Big Sur
Apple Mail (with her gmail)

Make off-line local backups before you begin (as you have already done). Then use Migration Assistant to move all your content.

There’s really no disadvantage to doing this. In the absolute worst case, you can always boot into Recovery mode, wipe the computer and start clean. But why create extra work for yourself when you probably won’t have to?

1 Like

Personally…I would migrate it rather than clean install and see if the crashing continues…if so then it is software. If not…problem solved. If it is software…I would make her a new user account and set it up before doing a clean and new everything install as the former is a bit easier. That way you’re not using too big of a hammer on the problem.

OTOH…if you would rather just be done with it…then nothing wrong with a clean install but that means every setup, setting, preference, and app needs to be reinstalled and configured.


Thank you both for your replies.

Very helpful to my wife’s grade C- tech support staff (that would be me :wink: LOL).

I’ll follow your advice.

My only challenge now is figuring out whether to use the CCC clone that is on an external drive connected to my Mac or her now old iMac as the source. I suspect if I don’t connect over our LAN then it will be decided by port/cable compatibility.

Any tips on that 101 question appreciated.

Again, thank you very much for your help and speedily too. Now she can open her Christmas present and we can get started. :wink: LOL

If it’s a relatively recent clone then I would use it since it will be a lot faster. If it’s not…boot the iMac into a separate newly created admin account and run another clone…then Migration Assistant from the up to date clone.

It works over the network…but is much slower. Depending on the drive…you might need a USB c to a converter plug…they’re cheap at Amazon…to connect the drive.

1 Like

Thank you very much.

However, I will readily admit to not being totally network savvy. So you’ve lost me a little.

I use CCC to “clone” (backup I believe Bombich uses) to an external drive connected to my Mac. It backs up both computers nightly.

So will Migration assistant “like” a CCC backup for the source? I can attach the external drive directly to the new Mac and work from there rather than over the network.

However, I believe Bombich informed users that due to some Apple changes, it’s backups were no longer bootable. I may or may not be confused on that point. The current/old iMac being backed up is running Big Sur so that may answer part of the question.

Any clarification appreciated but if no time I totally understand.

Thanks much.

Yes, CCC and SD clones can be used just fine by MA. Just hook up the external drive to the Mac that MA is being run on and select it as migration source from there.

The change Bombich reported on affects both CCC and SD. The default clones they create for Monterey and Big Sur are not bootable. But that’s because these versions of macOS supply their own core system. Only your data/apps/settings need to be migrated by MA and hence the clone has all it needs even if it can’t boot by itself.

The practical difference is small: you used to be able to boot from just the clone and then install a new macOS onto the internal drive. Now you boot from Recovery, install from there onto your internal partition, and follow up with MA to copy over form your non-bootable clone. The only real difference manifests if/when an internal disk gets so corrupted/damaged that Recovery can no longer load. But that’s fortunately very rare.

1 Like

Yes and no.

If your source system is running Catalina or an older macOS release, you can make a bootable backup with no problems.

If your system is running Big Sur (not sure about Monterey) on an Intel Mac, you can make a bootable backup, but with a few gotchas.

  • The only way to make a bootable backup of a Big Sur system is to use an Apple internal utility, which doesn’t support incremental backups. This is because of the signed system volume. If you try to make a backup of the System volume through any other mechanism, the result won’t be bootable.
  • So, although you can make a bootable backup, you have to completely wipe the destination as a part of doing so.
  • So, if you still want to make a bootable backup, do it once. Then make a normal backup of the Data volume, which can be done incrementally.
  • If all this is too confusing, or if you don’t want to bother with it, there’s no reason why you can’t just forget about a bootable backup and make a (non-bootable) backup of the Data volume alone.

If your system is an M1 Mac, then you pretty much can’t make a bootable backup. So just make non-bootable backups of the Data volume.

Having a non-bootable backup isn’t as big a deal as it used to be. All modern Macs support booting into Recovery mode. If your Mac completely fails, you can boot into Recovery mode, reinstall macOS from there, and then use Migration Assistant to recover everything from that backup.

All this having been said:

  • Don’t try booting or cloning a backup from your old Mac when setting up the new one. That will definitely fail if the new Mac has an M1, and I wouldn’t trust it if it’s an Intel Mac, unless it’s the same model as your old one.

  • If you made a non-bootable backup (Data volume only), Migration Assistant should have no problem migrating your apps and data from it.

  • I read somewhere that if you have made a bootable backup, that Migration Assistant may not be able to migrate from it. But I’m not certain about that bit.

  • If you have a Time Machine volume from your old Mac (which only backs up the Data volume), then Migration Assistant can definitely migrate from that.

  • You can always migrate directly from your old Mac, either via Target Disk mode or by running the Migration Assistant app on it (moving the data via Wi-Fi or Ethernet).


Thanks Simon.

That education is very helpful practically for this current project. Plus, being the curious sort, I now better understand what is going on during the migration and with Apple’s new core system. I like that.

Thank you. I appreciate.

When restoring after a drive failure, you used to be able to boot from your clone and then clone it onto your (newly replaced) internal drive.

I did something like this back in the PowerPC days. I maintained two bootable partitions on my hard drive (one for my normal work and one “emergency” partition, which I would occasionally boot in order to keep it’s OS installation up to date). I also generated a bootable DVD that included my backup software (which was Retrospect).

When I had a catastrophic internal drive failure, I replaced the internal drive. Then I booted the DVD and ran Retrospect to restore everything (OS, apps, documents, etc.) from my tape backup to the newly installed drive. It worked great.

Today, that’s not possible - you need to install macOS separately via an Apple installer (whether via Recovery or a bootable installer flash drive) and then migrate/restore a backup of the data volume. Not nearly as convenient, but it works.

Then there’s Internet recovery, where your Mac will download a bare-bones Recovery volume, which you can use to jump-start the process.

It can get to be more of a pain if you have an M1 Mac and the internal Recovery APFS container gets trashed. Then even Internet Recovery won’t work. You’ll need to restore it from another Mac using Configurator.

The only time you’re completely out of luck is if you’re on an M1 Mac and your internal SSD is completely trashed to the point that you can’t create/install/restore the recovery container. That will require Apple to get involved, which will probably involve a motherboard swap, since Apple service techs aren’t allowed to (and probably don’t know how to) replace soldered-down flash chips.

But the way I see it, that kind of failure is equivalent to any other kind of critical motherboard failure that could have happened in the past. It’s rare enough that you shouldn’t have to concern yourself with it.

OP back.

Thanks for all the help.Questions answered.

I appreciate the TidBITS Talk support.

1 Like

Yep…it will like it just fine.

Clone the old Mac to the drive.

Create an admin account on the new computer that’s a different name than on the old one…this can actually be the same one and Migration will offer to overwrite the homedir contents for you but a different name is less confusing.

Plug the drive into the new iMac and launch Migration Assistant…follow the prompts and proceed along. The macOS stuff from the clone will not get migrated even if both are the same version of macOS but all the apps, preferences, user accounts, and data will get copied.

This process is the same regardless of whether you use the new non bootable clone technique or the older bootable clone technique in CCC that for now at least still produces a bootable clone…but you don’t need the macOS part anyway…Monterey and Big Sur (and maybe Mojave, can’t recall exactly and too lazy to go google it) all use the sealed and signed system volume but Migration handles all of that for you.

When you’re done…make sure your wife’s everyday use account is not an admin one…it is safer that way. Should you or she need to something that requires the higher rights of an admin user…even if logged in as a standard or non admin user…macOS will prompt for credentials…simply replace the username suggested which is the currently logged in user with an admin account and the associated password and whatever needed admin rights will progress merrily along.


Really appreciate.

Thanks much,


Just to clarify, you don’t need to manually run this utility. CCC will run it for you when you try to make a bootable backup of a Big Sur system.