How do I properly adopt existing home folder on external bootable drive for an user on internal?

[yellowhelicopter]

Hi. So the situation is as follows. I've been using macOS installed on external bootable m2 drive (it's just much larger: 1TB vs 256MB internal), but now I want to use the internal drive for macOS instead, leaving my existing home folder on external.

Now I don't quite understand how to do it properly so that access rights/ownership wouldn't be broken. I'm going to use Migration Assistant to copy my apps from external but I'm not sure what do I do with the home folder/settings. If I also choose to migrate the user folder, the system will copy all its contents to internal, but I want to leave it where it is, or at least in some other place on external drive. Do I just create new user on internal, migrate apps, then change ~ path in Users & Groups to point to my existing home folder on external, and then fix ownership rights somehow? Or there is some more proper way?

Of course I could just migrate the user account with the home folder to internal with the Migration Assistant (leaving some big folders behind) and then move it back to external changing the ~ path in the Settings, but I'm feeling that would be some unnecessary actions moving it back and forth.

 

[Fishrrman]

Can you tell us:
- WHICH Mac you have ?

Whether it has an m-series CPU or Intel CPU is important.

If it's an Intel CPU, you could just boot from the external drive, then erase the internal drive, then use either CarbonCopyCloner or SuperDuper to "clone over" what you wanted.

CCC would actually be better in this case, because you can "selectively choose" WHAT you want to be cloned (SD cannot do this).

Another way:
First, determine how many accounts will be migrated.
Will it be only one? Or... more than that?
Then...
On the internal (target) drive, create a new, "temporary" administrative account. Check their ID numbers -- if there's already a user account with ID "501", the next one will get "502", etc.
You want your "main" account to be ID 501.
So... with the temporary account created (502), you can DELETE your [formerly] main account on the internal drive, leaving only the temp (502) account.
NOW...
When you use migration assistant to bring over your main account from the external drive, it will "flow into" the vacant 501 ID spot.

Another way:
If the Mac you have has an m-series CPU, you can use the "erase all content and settings" option (system preferences) to literally "wipe it clean", leaving it in an "out-of-the-box" state (ready for a new setup).

Then, run through the setup process, and when prompted by setup assistant, you can migrate your apps, accounts, settings and data from the external drive.
WARNING:
The size difference could come into play here, if you have too much stuff on the external to "fit".

There are other ways, as well.
The important question:
Will everything fit?

 

[yellowhelicopter]

My Mac is Mini M1.

As I've got it you're essentially saying how to move my account (with the home folder) from external to internal, right? But the whole point of my question was how to leave the ~ folder on external without moving it, instead "adopting" it by a new account on internal... if it's possible. If not, I guess I'll have to first "migration assist" it to internal and then move it back to external (changing ~ path in Users & Groups) - it just seems like unnecessary and stupid file moving back and forth.

 

[Fishrrman]

OK, it's an m-series Mac.

My advice:
"Wipe clean" the Mini, using the "erase all content and settings" choice in System preferences. Doing this will "restore it" to an "out-of-the-box" condition with only factory-installed software on it.

Then, do a "fresh setup".

You have a couple of choices:
ONE
You can try to migrate from the external drive. You may very well run into "not enough space" problems, because you "bought too small" with a 256gb internal SSD.

TWO
You can "set it up fresh" with a new account using the same username and password as your existing (old) account.
HOWEVER... just because you use the same name and password doesn't mean you can just "move stuff right over", because there will be permissions problems.

HOW TO OVERCOME PERMISSIONS PROBLEMS:
a. Get the new account set up and running from the internal drive
b. Connect the external drive.
c. Let the icon (for the drive) mount on the desktop. DO NOT "open" it.
d. Click on the icon ONE TIME to select it, then bring up the "get info" box (you can type command-i)
e. Click the lock at the bottom of get info and enter your password
f. Put a check into "ignore ownership on this volume" (sharing and permissions)
g. Close get info.

Now you can copy stuff from the external drive to the internal drive, and whatever you copy will "fall under the ownership" of your NEW account.

IMPORTANT notes about what can be copied and what can't (in your home folder):
You CANNOT copy "the top level of folders" from one home folder to the other.
By "top level of folders", I mean folders named pictures, documents, movies, music, etc.

However... you CAN copy files and folders that ARE INSIDE OF these folders.
By that I mean you can open the Pictures folder, and then copy the Photos library icon from the external drive to the internal drive (replacing the one on the internal drive).
This works the same with the other folders in your home folder, as well.

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Good luck.