How to move (copy) backed up files from a Time Machine drive to a new external drive?

My daughter has a new iMac. We want to use the internal storage on the new iMac for the System and Applications, and use an external SSD drive for her files (a lot of them, more than the built-in storage).


I'm using Migration Assistant to bring in the System and Applications from the TM backup of her old iMac.


How do I get her backed-up Desktop and Documents, etc., from the TM backup of her old machine to use from the new external drive?


Thanks in advance for your help!


Ed in Brooklyn

iMac (M1, 2021)

Posted on Jul 16, 2025 12:01 PM

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Question marked as Top-ranking reply

Posted on Jul 16, 2025 2:49 PM

"Enter Time Machine" then two-finger tap the item (folder in this case) you want to restore, then Restore To... and choose a destination. Repeat for the other backed up items or folders.


If I understand you correctly, you selectively migrated certain items (but not everything) from the older Mac's TM backup. That's perfectly ok and the right thing to do. However, be advised that having done that, the new Mac will continuing backing up to that very same backup drive. Perfectly ok as well.


The factor to be aware of is that once the new Mac starts backing up to that drive, items that are not present won't be backed up. That fact ought to be obvious on its face, but what may not be obvious is that items not present on the source Mac are considered to be "candidates for deletion" on future backups. That means they will be erased if and when Time Machine needs the space they occupy on the backup.


So... perform that restoration of items backed up before TM has a chance to do that.

3 replies
Question marked as Top-ranking reply

Jul 16, 2025 2:49 PM in response to Edward M. Baum

"Enter Time Machine" then two-finger tap the item (folder in this case) you want to restore, then Restore To... and choose a destination. Repeat for the other backed up items or folders.


If I understand you correctly, you selectively migrated certain items (but not everything) from the older Mac's TM backup. That's perfectly ok and the right thing to do. However, be advised that having done that, the new Mac will continuing backing up to that very same backup drive. Perfectly ok as well.


The factor to be aware of is that once the new Mac starts backing up to that drive, items that are not present won't be backed up. That fact ought to be obvious on its face, but what may not be obvious is that items not present on the source Mac are considered to be "candidates for deletion" on future backups. That means they will be erased if and when Time Machine needs the space they occupy on the backup.


So... perform that restoration of items backed up before TM has a chance to do that.

Jul 16, 2025 2:43 PM in response to Edward M. Baum

You can NO LONGER move backed up files on a Time Machine External Hard Disk to a new drive. The ONLY method I can think of to do this is to use Time Machine to migrate to the new Mac and then install the new External Hard Disk you intend to use for Time Machine for the new Mac. Let it back up and then it will have backed up (or moved) the data that was on the old Time Machine External Hard Disk to the new External Hard Disk.


What you are attempting to do is migrate from a larger capacity drive to a smaller capacity drive. This is strongly NOT RECOMMENDED as it is iffy at best and likely to fail. The wise thing to do is buy a Mac that has an adequate amount of storage on it to migrate to.


We get posts like this yours all the time on these forums and the answer is always the same. Just don't try it, it's likely not going to work due to have an insufficient amount of storage on the new Mac. People try to save money by purchasing a new Mac with an inadequate amount of storage and just end up with a mess on their hands. It's smart to save more money up and buy the right machine in the first place.

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How to move (copy) backed up files from a Time Machine drive to a new external drive?

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