How to install System on internal disk and user on external disk

[pwm86]

I come from an iMac 2015 with 1 TB and got now an iMac 2019 with only 256 TB internal disk. I managed to install the whole system on an external disk (Samsung T5). I would like to install the system on the internal SSD and my user on another externel one (Smsung T7).
I have asked chatgtp how to do thisvia a time machine backup, but it did not work: the migration assistant replaced the user on the external SSD by on on the internal and the complained about not enough space.

Please, tell me how to do this.

 

[Bigwaff]

Not recommended configuration for the non-techie. Search the forums here or the web. Want you want to search for is how to migrate or copy your user “home folder or home directory” from internal to external storage.

Example YouTube video

 

[Fishrrman]

Agree with Waff.
If you are asking how to do this, then you probably shouldn't be attempting it.

Either boot and run from the external SSD (as it is now, right?)
or...

...You could set up the internal SSD (which should be faster) with the OS, apps, and a "reduced-size" home folder.

By "reduced size", I mean that you keep your "large libraries" (such as Photos library, movies, music libraries) on the external drive. The apps that access them (examples: Photos, Music, etc.) won't have any problems if the libraries are "external".