Transfer from ancient iMac to new

I’m going to be helping a friend transition from her 12-year-old iMac (running Lion) to a brand new machine. I’m thinking we’ll use the Migration Assistant, but I’m wondering if there will be any issues I should be on the look out for?

About the connection: Apple’s instructions seem a little unclear on how best to make the connection in this case. Should I use an ethernet cable? Or WiFi?

First off, make one or two full backups of the old iMac before you begin. Just in case something goes wrong.

If you want to migrate via the network, use Ethernet if you can. It is faster and more reliable than Wi-Fi.

If you can’t migrate via the network (as was the case when I upgraded my Mac last year - the source machine can’t enter migration mode if it is running the Server app), then you will have to migrate via its hard drive. There are three ways to do this:

  1. Migrate from a Time Machine backup of the source machine. You should be able to pick the specific backup (date/time) to migrate from, just in case you don’t want to use the latest backup.

  2. Migrate from a clone of the source system’s hard drive.

    This is what I used for my migration. I connected the backup drive over FireWire (using several adapter dongles), since that performs better than USB 2.0, and did the migration over that connection.

  3. Migrate from the source system’s hard drive itself by putting it into Target Disk mode. This will, of course, require a compatible connection between the two. If your iMac’s Target Disk mode runs over FireWire (as I think all Macs from that era do), then you’ll need some adapter dongles to connect it to your new Mac.

Or, given the age, maybe you don’t want to migrate at all. Since a lot (maybe most) of your apps aren’t going to be compatible with the new Mac (nothing 32-bit works on macOS 10.15 and later), it might be better to just create login accounts on the new Mac, use normal file sharing to copy all your documents from the old Mac to the new one, and then manually install your apps. This will probably take longer, but you might find it easier, especially if the migration doesn’t go smoothly.


There is a limit on how far back in terms of macOS versions that will be compatible with that new machine, but I’ve never run across such a list. So don’t be surprised if after wiring up the two Macs and choosing to migrate if it fails or refuses. Have a plan B along the lines that David suggested on backups that can be used to Finder copy Home folder, files and compatible apps.

If using Migration Assistant, why would you ever choose to use a connection between the two computers rather than a TM backup connected directly to the new machine?

That said, I suspect David’s suggestion not to use MA at all might well be very sensible. Acquisition of a new machine is a good opportunity to clear out accumulated crud.

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I echo @jbr in preferring to use an external drive with a clone or TM backup as the source of the migration. It will general be more reliable and faster than making a network connection between the two machines. If you do need to go the network route, definitely connect via Ethernet and not Wi-Fi.

Thank you all for the suggestions. I’m considering a manual transfer of files, but I’m wondering about email (Apple Mail)? I’m not sure how to transfer that without using MA.

If your Mail app is configured to use IMAP, then you don’t need to do anything special. Just add the account to the Mail app on the new computer and it will pull everything from the server.

If you have locally-stored messages (the “On My Mac” folder), you have a few options:

  1. Move them to a folder on the server. Then the new Mac will see them. But this may be problematic if you have a lot of locally-stored files. You may hit the server’s storage limit and it could take time to re-upload everything.

  2. Export that folder (to a .mbox file). Copy it to the new Mac and import it over there.

  3. Copy over the contents of the Library/Mail folder from the old Mac to the new one. This should cause the new system’s mail app to upgrade the internal database to the latest version, but since your old system is so old, I’m not certain it will work.

If you choose Migration Assistant, follow the instructions precisely in the order in which they appear. Specifically, if you get a message that says you may skip this step and perform it later, don’t do it. That path has twice led me to infinite problems that could only be solved by upper level Mac experts.

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If it’s the new M1 iMac, make sure you have the correct adapter and cable when using MA. I think manual setup is best in your scenario.

Over the years, I’ve had no luck with Migration Assistant, even though I’m an experienced Mac user. The most recent time I tried it resulted in a big mess of confusion, complication, and corruption. (Files and my brain.) I’m not the only one who’s had this happen.

I did find a Step-by-Step Guide to Manual Mac System Migration online, but it’s rather old. Still, the two systems I’m migrating between (from Mavericks on a Mac Pro to High Sierra on an iMac) are also rather old.

I’ve been slowly trying some of that page’s tips. If anyone can recommend other online guides to this process, I’d appreciate it.

The one most useful thing I’ve learned over the years, to make migrations easier, is to use a completely separate drive for my documents. That way I only have to deal with the system stuff + applications, not worry about my personal files getting screwed up in the process.

I’m currently doing something similar for my wife, with 6 year old MacBook Air to an M1 MacBook Pro.

Personally, I prefer to take a little extra time… well… a lot really and just start fresh with the new machine. A lot has changed in the OS in 6-10 years and Migration Assistant is going to be doing a good deal of shifting behind the scenes. So instead, I install the essential apps and then add as we go anything else that is missing. A lot of unused stuff gets removed and the system remains super-clean going forward. iCloud makes this very easy, as everything associated is auto-installed, e.g. email accounts. For other things, like Filemaker, I download the latest, which is M1 compatible and do a clean install. So Rosetta2 isn’t installed, which I assume it would be if I was doing a Migration Assistant transfer.

In the grand scheme of things, it’s a small amount of extra effort.

I think the key here is the definition of ancient. If the old Mac is reasonably up to date macOS-wise then Migration Assistant works pretty well. If it is 4 or 5 generations of macOS behind…then I would start to think about doing a clean migration. For that…I would sign out of iCloud and any other cloud services and subscriptions…then given the changes in the Mail database over the years I would make sure that all the mail was on either an IMAP server, and any local only mailboxes I would export to mbox files.

Migration Assistant over user accounts and home directories since that’s the easiest way to get the permissions set right. Reinstall software and sign into subs and iCloud…launch Mail and let it do the mail migration thing since the mbox files provide a way to recover if that doesn’t work right.


My iMac 27" 2014 model has been obsoleted by the next release of macOS (Monterey) which, frankly, I resent. I have decided to wait for the new model to be available – maybe 30", maybe in 2022, maybe never, who knows?
The good news is that this will give me a chance to build the machine from scratch. While the current iMac was bought in 2015, the contents were migrated from an earlier iMac bought in 2010. The result is that there is a lot of software which is either no longer used or, perhaps, explains some of the strange behavior my machine exhibits since Big Sur came along.
Building from scratch is a non-trivial exercise and requires careful planning. I have developed a 8 page set of step by step instructions detailing all the customization of all the system preferences and application options that I have become accustomed to. Migrating data files, while time consuming, is the simplest part of the exercise.
I would not recommend this approach unless either you are pretty tech-savvy or you never change default OS or application preferences.

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Are your “step by step instructions” something that might be helpful to other people (in case you’d care to share), or are they too specific to your setup to help others who are migrating?

Very specific: system preferences, MS Office preferences and menu bars, web browser settings and extensions, a list of apps to download and their settings, Terminal commands for obscure macOS settings, and instructions to transfer a Backblaze account between machines. You accumulate a lot of stuff in 11 years!