How to transition Time Machine volume to a new Mac?

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How to transition Time Machine volume to a new Mac?

I'm about to migrate to a new Mac. Current Mac is running macOS 12 Monterrey and can't be upgraded, new one presumably will be macOS 13. Volume name of the startup volume will be the factory default, "Macintosh HD," on both Macs.

I plan to to the migration via WiFi transfer between the Macs, because past experience has shown that migrating from a Time Machine backup is excruciatingly slow, far slower than Mac-to-Mac WiFi.

Say the new Mac is up, running, and migrated. Let's also say I don't want to reformat the Time Machine drive and start from scratch, losing all the backup history from the old Mac.

I'd like to be able to attach the old volume and have the past history be recognized as the past history for the new machine so that I can e.g. recover month-old versions of files. I don't want to have Time Machine grind away doing a complete backup of everything on the new Mac, as if it were an entirely new volme.

What do I need to do to make sure that the old Time Machine volume is recognized as the "past history" of the new Mac? Does macOS automatically treat the boot volume on two different Macs as "the same" volume for Time Machine purposes?

Mac mini, OS X 10.11

Posted on Apr 12, 2023 6:24 AM

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Answer 1

Top-ranking reply

Daniel P. B. Smith Author

Level 2

291 points

Apr 21, 2023 6:00 AM in response to dgerman

I transitioned by creating a bootable copy of my system drive, using Carbon Copy Cloner's "legacy bootable copy" feature, on a 1 GB external SSD drive. I ejected the SSD drive and the Time Machine drive and disconnected them from the old Mac. I have Time Machine set for manual backup.

I connected only the external SSD drive to the new Mac and started it up for the first time. I chose migrate "From a Mac, Time Machine backup or Startup disk" and choose the external SSD drive as the source. Things went smoothly and I found myself back in "the same world" as before. During the process I was not asked any questions about Time Machine.

After migration, I connected the Time Machine drive and it appeared in the Finder. I checked Time Machine and it showed that this drive was the Time Machine drive. For laughs I tried "Explore Backups on Time Machine." None were shown.

I tried "Make Backup Now." At that point, I was asked if I wanted to "inherit" the existing backups, and warned that if I did, I could no longer explore them on the previous Mac. I went ahead. The "inheritance" process was almost instantaneous. After giving plenty of time (an hour or so) for everything to settle down, I found that a) "explore backups" now showed all of the old history, and that the backup had been an incremental backup of changed files. In other words, just what I wanted.

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Answer 2

tbirdvet

Level 6

17,793 points

Apr 12, 2023 11:20 AM in response to Daniel P. B. Smith

When you migrate from old to new all your settings remain so no issue there. However, I would not recommend migrating using WiFi as that connection may fail midstream. Even though it may slower(for you) using a TM drive it is the most reliable process. Also when you have your TM drive backup the new Mac you may find it difficult to access old files from the drive before the update. It is best to start a new backup with a new drive and save the old one just in case (or erase old drive and make a new backup).

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Answer 3

dgerman

Level 1

28 points

Apr 13, 2023 8:42 AM in response to Daniel P. B. Smith

Please update this with your results success OR failure.

Thank you.

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How to transition Time Machine volume to a new Mac?

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