I give up. I have a new mini with a 256 GB SSD, plus a 1TB lightning SSD attached. I can place individual OS parts where I want, but that doesn't mean that they will work. They don't. How am I supposed to squeeze 3/4TB of data onto two different drives in the mini in such a way that they will function? Yeah, right, Migration Assistant is supposed to take care of it? Right. Doesn't work.
Mac mini, macOS 12.2
Assuming your Time Machine volume is in an APFS container on the external SSD, create a new APFS volume in the same container. The new volume will share the available storage space.
Next, use Migration Assistant to install apps and system settings without user files on the internal drive.
Then, manually create user account with user folders on both the internal and external SSDs. Use Finder to copy folders from the Time Machine backup volume trying to balance the data between the internal and external storage. Files needing backup with Time Machine (in a new backup set) should, where possible, be placed on the internal drive.
If this works as intended, delete the old Time Machine APFS volume and create a new one as below using Terminal. Once created, add to the new volume to Time Machine (you should also consider using Time Machine options to exclude the external user folder).
diskutil apfs addvolume diskn APFSX "Time Machine-1" -quota nnng -role T -passphrase phrase -passphrasehint hint
(where diskn is the APFS container disk and nnn specifies the number of GB allocated to Time Machine; note that the passphrase and hint are only specified when encryption is required)
Hope this helps.
P.S. I thought it might be possible to use Migration Assistant to move user data piecemeal (e.g. separate user accounts) but this seems not to be possible in your case
Assuming your Time Machine volume is in an APFS container on the external SSD, create a new APFS volume in the same container. The new volume will share the available storage space.
Next, use Migration Assistant to install apps and system settings without user files on the internal drive.
Then, manually create user account with user folders on both the internal and external SSDs. Use Finder to copy folders from the Time Machine backup volume trying to balance the data between the internal and external storage. Files needing backup with Time Machine (in a new backup set) should, where possible, be placed on the internal drive.
If this works as intended, delete the old Time Machine APFS volume and create a new one as below using Terminal. Once created, add to the new volume to Time Machine (you should also consider using Time Machine options to exclude the external user folder).
diskutil apfs addvolume diskn APFSX "Time Machine-1" -quota nnng -role T -passphrase phrase -passphrasehint hint
(where diskn is the APFS container disk and nnn specifies the number of GB allocated to Time Machine; note that the passphrase and hint are only specified when encryption is required)
Hope this helps.
P.S. I thought it might be possible to use Migration Assistant to move user data piecemeal (e.g. separate user accounts) but this seems not to be possible in your case
I have macOS, applications, and user accounts stored on the internal SSD (256 GB). Media files (photos, videos, music) are stored on an external (500 GB) SSD which shares space with Time Machine (backup of internal drives only). In addition, I have a second external (500 GB) SSD which I use to store older versions of macOS, RAW image files, and a second Time Machine volume.
The Migration Assistant has an option to select which files that you want to migrate. It is also possible to place user home directories on an external drive (see below).
[Image Edited by Moderator to Remove Personal Information]
See information below about relocating a home folder. A symbolic link is suggested as one option.
[extracted from https://discussions.apple.com/thread/253623300]
One last point ...
Should you run out of storage on the external drive while copying user files to the external drive, consider using a large capacity USB key or cloud storage as temporary storage. These files would then be moved back to the external drive once the original Time Machine backup has been deleted.
My preferred method to is create a disk image (of a folder) using the Disk Utility (must have Full Disk Access privilege to access external drive). Although it requires an extra step, once created it mounts like a disk volume.
I'd like to keep my desktop in one piece, but it alone demands more space than the entire 256GB SSD. At the moment, it's on an external Thunderbolt drive, but the Users file on the boot drive doesn't see it. Would a symlink do it? I used Migration Assistant to move some items from the Mac Pro, but I didn't see a way to make one installation connect with another. I had trouble with Apple Music, but the problems were mostly solved by squeezing all my music files onto the scant space on the boot drive, but the Desktop is definitely NOT going to fit.
Thanks for the tips, but I'm afraid none of them worked for me. You wrote: "It is also possible to place user home directories on an external drive (see below).", accompanied by photos of Disk Utility stages. Not possible to use Migration Assistant to place anything on an external volume in Monterey, at least not on my computer. There is no option to migrate files to anything other than the built-in drive of the mini. If there were, I would have used it by now. And I may not be an expert, but I don't understand how changing anything in Users & Groups would help matters. Can you enlighten me?
Here's an edited version of the Users & Groups (Advanced Options) System Preference:
Not enough room on mini
