MAC migration to new MAC with different (AFPS) file system?

Move your content to a new Mac

The New System is the new Apple Silicon M1 computer ?? Reason for asking - would strongly suggest Only Migrating your User Account and nothing more. If there were any problematic issues on Catalina and everything is Migrated from Catalina to Big Sur - the problems will Migrated to an otherwise virgin install of Big Sur. That and Applications from Catalina do not automatically translate to functioning well on Big Sur and Especially if moving to the M1 CPU.

Yes. As Catalina is already AFPS you don't have an issue there.

An important point: do not create a user on your new Mac before doing the migration. Simply import the user from the old Mac. If you create a user first with the same name, the imported user will have a modified name and then you will have a lot of permissions problems transferring data to the newly formed user.

Catalina is already APFS. Problems may be related to apps or extensions not compatible with Big Sur. Give a check and if everything is OK I do not see problems. I migrated from iMac 27" Catalina to MacMini M1 Big Sur with insignificant problems. Works like a charm.

(Sorry, I wanted to answer to mr-ed)

When I booted my new M1 mini and went through the setup process, I plugged in my Mojave Time Machine backup drive, and let Migration Assistant put all pertinent files and settings onto the M1 mini in the user folder that the setup process had just made. Consequently, on first boot, all of my Mail, configuration settings, etc. were exactly like they were on Mojave. It just worked.

Your files and folders, when migrating between two APFS formatted operating systems, are like leaves floating on a pond, and the underlying file system partition type is irrelevant.

The Time Machine Backup used on the Catalina computer is probably in the older HFS Journaled / GUID Partition Map format.

Regardless of this - the Migration Assist on the New Apple Silicon M1 can still read and write to HFS Journaled drives.

The issue, might be, when setting up a New Time Machine Backup on the M1 CPU - Time Machine Backup may want to Convert the New Drive to the new APFS / GUID format.

Notation : If reusing the same Catalina Based Time Machine Backup Drive on the New M1 computer - the Old Catalina Backups may become totally unusable in the future.

Personally - would keep the existing Drive with the Catalina Backups aside and in safe place. On the New Machine - start fresh with a new & empty Drive.

From what have seen, the drive is Reformatted to APFS with the GUID Partition Map should work fine for Time Machine Backup on Big Sur.

If using on Catalina - reformat as HFS Journaled and GUID Partition Map.

If it's a firmware limit, then OK. No way to bypass it.

If not, then can be erased via terminal and initialized in APFS. Using an SSD in hfs+ instead of APFS (which has lots of features for major speed and for a longer life)...

Good luck!

These thing happen from time to time :-)))

Ok. But still don't understand "because APFS not on Catalina" as APFS is in Mac OS from 10.12 Sierra...