How do I inherit Time Machine backup from an old MacBook Pro on a new one?

New m4 MacBook Pro, running Tahoe, migrated from 2017 intel MacBook Pro. Everything is is fine, but I’ve hit a brick wall tying to inherit Time Machine backup from old machine. Tried terminal using both inherit backup and associate disk, both result in incorrect verb. Tried going back and using migration assistant never took me to inherit backup. Am I kidding myself that this is even possible, maybe a disk format issue?


[Re-Titled by Moderator]

Original Title: Inherit Time Machine backup

MacBook Pro 15″, macOS 13.7

Posted on Jan 3, 2026 7:08 PM

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8 replies

Jan 7, 2026 5:54 PM in response to alightman

Now there are two files on the backup drive, one for each computer.

"Files?" Should be a folder, either Timestamped (APFS format) or named for the Mac (older, HFS+ format). If they look like files and not folders, then is it a network backup? That is an important distinction that directly impacts your question.

They both work, 7 years of backup on the Intel Mac work fine on the old machine. New machine backing up normally, but won’t access old backups. Nothing erased, never a question about where anything should go.

If it is a network backup destination, then it will create a separate Sparse Bundle Disk Image for every computer.

If it is an APFS backup scheme on a direct-connected drive it must erase the drive to start over. There is only ever one APFS backup allowed on a volume.

If it is using the old HFS+ scheme, then it probably recognized that on the drive and created a new folder, but both should be inside a Backups.backup folder (doesn't sound like that).

Jan 3, 2026 8:13 PM in response to alightman

Normally, all that's needed is to use Migration Assistant then connect the backup to the new Mac, and you are prompted to claim the backups on the drive.


"Your Mac might ask whether this computer should claim existing backups created on a different computer. Claim the backups if you want them to become part of the backups for this Mac."


Back up your Mac with Time Machine - Apple Support


https://eclecticlight.co/2024/11/12/migrating-to-a-new-mac-and-claiming-time-machine-backups/



Jan 7, 2026 5:47 PM in response to alightman

Just to update, I gave up on the idea of keeping the old backup, I have most of what I need in other places. Went ahead and did a TM backup with the new machine. Now there are two files on the backup drive, one for each computer. They both work, 7 years of backup on the Intel Mac work fine on the old machine. New machine backing up normally, but won’t access old backups. Nothing erased, never a question about where anything should go.

How do I inherit Time Machine backup from an old MacBook Pro on a new one?

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