Detailed view of MIGRATION ASSISTANT?

[toke lahti]

Apple doesn't give as very detailed view.
Has anybody gathered a detailed info of what each option really copies?

1. What "User accounts" copies and what not?
2. "Documents and files from apps", where are these collected from? /Library? ~/Library? Somewhere else outside the home folder?
3. "Computer settings", there are user based and global settings, how are these handled? All settings from my accounts System Settings are copied? Or just some? What is and what is not?
4. "Apps", also can be global or user based, does MA copy both and all their settings?

I don't like this secrecy. I've been dragging my account from mac to mac for 19 years and I'd like cut some junk away now.
Price of storage is amazing, for how long? Rest of the decade?

 

[!!!]

Generally, MA attempts to copy everything over, except for log files and caches, if you keep every option checked.

What "User accounts" copies and what not?

Probably everything in the /Users/ folder.

"Computer settings", there are user based and global settings, how are these handled? All settings from my accounts System Settings are copied? Or just some? What is and what is not?

Everything. The goal of MA is to make the transition as seamless as possible.

"Apps", also can be global or user based, does MA copy both and all their settings?

Apps only refer to the executable .app itself, macOS doesn't really have knowledge of the connection between the app and its preferences/application support (unless the app is sandboxed).

"Documents and files from apps", where are these collected from? /Library? ~/Library? Somewhere else outside the home folder?

Presumably.

I don't like this secrecy.

I don't think it's secrecy so much as Apple trying to create user-friendly names for each of these categories which end up obscuring the technical aspect, and then Apple doesn't document many things very well nowadays. As I said, the general goal of MA is to copy over as much as possible, so the transition is as seamless as possible. Disabling something seems pointless at that point, why wouldn't you want to copy everything over if you're using MA?

I've been dragging my account from mac to mac for 19 years and I'd like cut some junk away now.

If your goal is really to get in there and remove the crud, then I think you'd be better off starting with a fresh setup and manually copying things over from your backup drive.

 

[toke lahti]

Gemini says:
"Other files & folders" in Migration Assistant, you are telling the tool to copy files located outside of the standard, predefined user folders (like Desktop, Pictures, Documents)."

Does this mean that when you choose "User accounts", it copies only "standard" pre-existing folders, like "Documents", "Music", etc., but does NOT copy any folders user has created in homedir?

Or Gemini is hallucinating and "other" means everything outside of your /Users?

I'd still like to know what is included and excluded in "Computer Settings".
If it includes ALL, then it will copy all of ~/Library/Application Support (corrected from "Assistant")? Which I (of course) do not want.

I do not understand why this info has to be hidden.
You can give "user friendly" Guide and also deeper knowledge to those who want it.

Oh well, maybe I make this a hobby and grab an old ssd, try every option and document the results.
Maybe nobody else would ever do this?

 

[Brian33]

Does this mean that when you choose "User accounts", it copies only "standard" pre-existing folders, like "Documents", "Music", etc., but does NOT copy any folders user has created in homedir?

In my experience, Migration Assistant does copy "non-standard", user-added folders that are created within your home directory. For example, alongside the standard Documents, Downloads, etc., I have created "Audio Projects", "Backups", and "Development" at the top-level of my home directory. MA copied all with no issue.

EDIT: I should add that my latest MA experience is going from Monterey to Sequoia.

"Other files & folders" in Migration Assistant, you are telling the tool to copy files located outside of the standard, predefined user folders (like Desktop, Pictures, Documents)."

Yes, this category is pretty vague. All I can say is that for me it did copy everything in '/usr/local' (where I have some custom stuff, and Homebrew was located). Homebrew now installs at '/opt' and I would expect that would fall into this category also.

Perhaps it includes custom-configured stuff in '/etc', as there are a lot of Unix style config files there (e.g., newsyslog.config, fstab, sudoers, etc.) which a few people may have customized. Or perhaps those config files count as "system settings" -- who knows!

Like you, I really wish all the Migration Assistant categories were well documented. There's no good excuse for Apple to leave us guessing when we do a system migration. 😡

 

[Brian33]

I'd still like to know what is included and excluded in "Computer Settings".
If it includes ALL, then it will copy all of ~/Library/Application Assistant? Which I (of course) do not want.

Me too. But what is '~/Library/Application Assistant'? It doesn't exist in my ~/Library.

Perhaps you mean '~/Library/Application Support'? If so, I think that it IS copied in its entirety by MA if you choose "User Accounts".

 

[toke lahti]

I finally found energy to do this testing.

I have Sequoia clean installed to a new drive. And made an image of that, so I can always return to clean install.
I make all Migration from using the new install.
I'm using DiskCatalogMaker to catalog what is in that new system drive.

First, "the vaguest one":
"Other files & folders"
That copied 2 major things for me:

1. /Users/Shared
2. /usr/local/Cellar
   (Homebrew's packet folder)

 

[toke lahti]

And, like I suspected; just problems.
Restoring the clean istall from container's image does not work.
I should have used CCC.
And maybe upgrade it to the latest.
Just more expenses...

 

[Brian33]

First, "the vaguest one":
"Other files & folders"
That copied 2 major things for me:

1. /Users/Shared
2. /usr/local/Cellar
   (Homebrew's packet folder)

'/Users/Shared' -- that's a good discovery! I didn't think to wonder about what Migration Assistant category that might include that!

And thanks for confirming that '/usr/local/Cellar' is included with "Other files and folders."

Also, I've remembered this interesting tidbit about MA:
when I went from Monterey to Sequoia, it DID migrate my modified '/etc/fstab' file to the new machine. Unfortunately, I had all MA categories checked, so I don't know if it fell in one of the "System & Network" sub-categories (probably), or the "Other Files and Folders" category.

(I use /etc/fstab to prevent the automatic mount of some of my volumes, and mount other, archive volumes read-only. Note that it must be altered only with the 'vifs' command, according to documentation.)

 

[Brian33]

And, like I suspected; just problems.
Restoring the clean istall from container's image does not work.
I should have used CCC.

I HAVE NOT TRIED THIS, but Howard Oakley reports that you can easily make a snapshot of your boot volume group's Data volume, and later easily return to booting with that snapshot by using Recovery Mode and Time Machine. (You don't have to be currently using TM for backup.) Effectively a complete "restore" to a previous point in time.

https://eclecticlight.co/2026/05/07/how-to-make-and-roll-back-to-a-snapshot/

I find this very interesting. It's not clear if it would work with, for example, CCC snapshots of the internal drive. It appears it would only work for snapshots in a bootable volume group. That is, not for any snapshots on a non-bootable external drive, like a CCC backup drive. Also not clear if the bootable volume group must be on the internal drive, or if it could be an external boot drive.

Try at your own risk, but if you do, I'd like to hear the results.

 

[toke lahti]

Wanted to make that jailbreak of those user accounts held prisoners by compressed image.
I got help from Gemini.

Wipe the new system drive empty. Install OS again and during installation, when it asks about Migration, magic shortcut:
Control + Option + Command + T !!!
Open the image from Terminal and then point MA to look from it. Easy peasy.

Another very useful idea from Gemini:
Make a small system disk for MA researching, then you can clone it to a small ssd and hopefully quite easily also clone it back. Will try to do that with CCC.

Doing all kind of weird stuff with images and booting here and there, I noticed that my internal ssd's system was not working. Then I learned, that I can't reinstall the system to it, since I had not made big enough system disk. (I had reserved most of the space to other use than internal "emergency" system. Then I learned that you can grow APFS container only if it's not at the "end" of the disk. I had normal GUID parition in the beginning, then free space and the the container. Done that manually a year ago.
It happens to be that GUID standard can't move the start of the partition, only the end location. How weird. Live and learn. So, new partitioning, this time the free space at the end of the disk, new Sonoma install and old local admin from TM backup.

There is an issue with DiskCatalogMaker, since it does show right the used space in APFS disk. But it seems to show numbers right with all the folders (recursively) inside that disk, so I will continue to next part...

 

[toke lahti]

First, "the vaguest one":
"Other files & folders"
That copied 2 major things for me:

1. /Users/Shared
2. /usr/local/Cellar
   (Homebrew's packet folder)

First step was 23GB in my case.
Now, step 2.
"Other data" from my user account.
Ouch!
Gemini's idea crashed.
You can't Migrate anything from your user account, without copying ALL & EVERYTHING from ~/Library.
Which in my case is 203GB.
And my new "easily cloned" system drive is 200GB.
Fortunately I do have now a spare 500GB ssd in hand.
I just need to do everything again.

...to be continued...

 

[benholt]

Went through this exact exercise last year off a 2019 iMac Pro, and the "all or nothing" ~/Library behavior is real — the byte count is almost entirely /Library/Application Support and /Library/Caches (Adobe disk caches, Redshift cache, Lightroom previews for anyone with creative apps). What actually worked for me: run MA with everything checked to a scratch external first, boot the new machine off that migrated system, then rsync-and-prune the specific subfolders you know you don't want. I keep a checklist for the usual offenders (~/Library/Caches/*, ~/Library/Application Support/Adobe/*/Disk Cache*, ~/Library/Application Support/Google/Chrome/Default/Service Worker, and any DAM tool's preview folder). Two other gotchas worth flagging before you start: if iCloud Drive's "Optimize Mac Storage" is on, MA copies placeholder stubs instead of the actual files — sign in on the target and let iCloud rehydrate before you nuke the source. And ~/Library/Keychains doesn't come over with User Accounts, it's part of the "Applications and settings" step, which is easy to miss if you're cherry-picking categories.

 

[Brian33]

And ~/Library/Keychains doesn't come over with User Accounts, it's part of the "Applications and settings" step, which is easy to miss if you're cherry-picking categories.

Wow, that is a surprise to me! Thank you for that information.

 

[toke lahti]

My step 3. was to migrate only "Applications".
Which for me meant 110GB in /Applications AND +21,5GB to /Library.
Most of that latter is /Library/Application Support, where I suspect, my problems of running this system are.

Booting to that MA'ed system had for the start tons of notifications about Extensions and Backgroung Items added.
That is the bloat I've been collecting almoast 2 decades now. There's no easy way to tell which are harmless and which are bad.
The whole idea of this experiment is trying to get my next system to work "like new".
My current Venutra (external) install takes minutes to boot, has at least one crast at every boot (or just before shutdown, it always reports it), recently it has done something new: all of a sudden I'm logged out. Sometimes when logging in, it's like from lockscreen, all apps & stuff is running and most of the time it is like after bootup, all things starting, which also for me means few minutes when everything is usable. There is always something like half minute, when everything halts, even the clock, only mouse is moving.
I also was worried about my old ssd's health, since I discovered that Trim is not working for it in Ventura (at least).
Of course, I started a thread here in forums about that. Enabling Trim caused bad hiccups to the system and probably still are. Can't recommend that to anyone using Ventura from external. After my new Sequoia install is my daily driver, I will reinstall Ventura to this old system disk and see, if there is any improvements.
I recently ran Hardware test to my mini2018 and there was nothing found.

Over the years I have installed many many old software that wanted or needed kexts, which then caused problems or not. One of the worst have been Logitech's different apps, since I own many their old mices, also some that are not mac versions and I always have tried how to best use their functions. Or just use at all. Samsung's "Magician" might also caused several boot loops, before the system tells that "all extensions are disabled", probably because the system can't figure out, which one is guilty. Then using some apps, there is a need to a certain extension and then the other and the combination and it's causes are olways mystery. Maybe somebody would have built a database collecting and illustrating that kext-verse, but I'm not that savvy.

If there is M5/6/7 mini with reasonable price (RAMageddon ended because AI bubble bursed), I might need to do new shift. Otherwise I will run that next syste at least 5 years. I usually upgrade OS every second year, since it has always been bigger mess to do. If I stick with mini2018, AFAIK, there is no upgrade from Sequoia, so it might be a long run with that.

So, my plan forward with MA is "everything but Applications".
Unless there are some very important remarks here in next 24 hours...

Btw, I've used DiskCatalogMaker through this process to compare the contents of different attemps. Very helpful.