I had MBP 2015 in the past and used Time Machine on it. Last September, I switched to MBP 16'' 2019 and did a fresh installation / manual copy of most of my home directory files, maintaining the layout.
Note: I wanted to do a fresh installation for various reasons but if I were to compare the filesystems in the end, they are almost the same – my home directory is still
/Users/borekb, the folder layout under it is exactly the same, etc.
Now I'm trying to set up Time Machine again but I'd like to continue with my previous line of backups – for example, I want to see last year's versions of files that are on the same path. Also, my first backup on this new Mac should be "incremental" – I'd like Time Machine to compare what is on my current Mac with the latest state of my previous backups (from September 2020) and does a diff as usual.
The key to this seems to be the
tmutil inheritbackup command, which I've successfully ran:
$ sudo tmutil inheritbackup /Volumes/time-machine/Borek’s\ MacBook\ Pro.backupbundle
Mounting disk image...
Unmounting disk image...
Inheriting disk image for machine...
Successfully inherited disk image '/Volumes/time-machine/Borek’s MBP 16.backupbundle'
/Volumes/time-machine is a mounted network folder (I backup wirelessly to a Synology NAS) and the command seemed to work well – it did this rename:
Borek’s MacBook Pro.backupbundle →
Borek’s MBP 16.backupbundle
I then went to Time Machine UI, selected the
time-machine disk, entered my previous password for encryption, etc.:
Everything seemed fine so far.
However, when I start backing up, it does a full initial backup to a new folder inside the
.backupbundle that is called after my new computer's name:
Borek’s MBP 16. This is what it looks like after I mount the sparse bundle and browse the
/Volumes/Time Machine Backups/Backups.backupdb folder:
I somehow want to tell Time Machine keep using the original
Borek’s MacBook Pro folder (the one that was last modified on 22 Sep 2020).
How to do that?
UPDATE 1: I tried changing my computer's name to match the old one but Time Machine still insists on creating a new set of backups from scratch – it just calls the new "machine directory"
Borek’s MacBook Pro 2:
I have also ran this script, found here (as Big Sur doesn't seem to support
-a), to run
tmutil associatedisk an all folders found under the original backup location:
for f in /Volumes/Time\ Machine\ Backups/Backups.backupdb/Borek’s\ MacBook\ Pro/*; do
if [[ -d "$f" ]]; then
sudo tmutil associatedisk /Volumes/Macintosh\ HD "$f"/Macintosh\ HD;
This also worked correctly but Time Machine still doesn't see my older backups and is attempting to create
Borek’s MacBook Pro 2 when I try to run a backup.
UPDATE 2: I've successfully verified backups which was a solution in this answer. The preferences UI still report "no backups" so I'm now trying to run a new backup, which was Step 2 in that answer and the author wasn't sure if it's necessary or not. I'll report back in a few hours...