Mini M4 with home directory on external drive: unable to log in at this time….

My original post was just to provide advice to deal with a situation that can arise if one chooses to move the home directory to an external drive. The cons and the pros of relocating that directory is a big topic I'd rather not spend a whole lot of time on. I agree that if you don't know what your getting into technically, you probably shouldn't do it.

Personally, having done machine language modifications to my Apple II way back in 1980, worked as a Unix/Unix-like sysadmin for many years and used a hackintosh for the last 5 years, I'm more than up for time & trouble. I learned at lot in the first two weeks with my new M4 mini, re-configuring it 4 or 5 times including testing various restore and recovery methods. Now its in production and I'm pleased and more than ready if/when a failure occurs.

Thanks for your reply. If those files were the only issue, those are good ideas. With ~800GB in my Documents folder, those suggestions don't address the issue given a 250GB internal drive. The problem is having everything in the places Apple has always designated and have access that is transparent to the user and applications. Some applications as you correctly point out provide for relocating the associated files.

If there is a way to relocate the Documents folder and be able to navigate as always to it, I welcome suggestions. I've had past experience with having my home directory on a separate drive and I agree that it is highly preferable to keep it on the internal drive. Even with everything now working smoothly with the home directory on the external drive, I'd have no problem moving back to the internal drive with a satisfactory solution.

And btw no reinstall would be necessary to use the internal drive; my original home directory is still there and is only a change in System Settings and a reboot away.

No problem - appreciate you taking the time to reply. As noted in my original message, booting from the external drive worked very well for me until I tried to use TimeMachine. It seems to want to access system files on the internal drive to complete its initial backup and fails. I couldn't find a work around. Also, I hear that Apple Intelligence will not function when booting from an external drive.

To match the 4TB of storage on my prior system, I'd be looking at a M4 Pro at about $2600. Yes, sure would have made this migration dead simple but I have more time to fiddle with technical workarounds than money. 8)

The error message is telling you that the system cannot access whatever folder you changed your home directory to. If you have another account on the system with admin privileges (something I recommend always having to provide access when your everyday user account gets messed up), log into that account. If so then test whether you can log into your user account via fast user switching. If you can, you may have the same situation I had where the external drive was not mounted until at least one user logs in. If not, go to System Setting and change your home directory back to its previous one. Reboot and see if you can log in. If so, your back in business. Then take the advice of others by leaving your home directory where it is and just creating a place for storing files in alternative locations. Not as clean as storing most things in Documents as Apple encouraged for years but safer.

If you don't have any other accounts with admin privileges, then booting into Recovery mode and reinstalling is your best bet.