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yugcameht
User level: Level 1 (0 points)

Migration Assistant fails to recognize Time Machine backup on MacBook

I recently had a 13” M1 MacBook with a broken screen in accompanied by a brand new M5 13”. The owner asked if I could migrate the user data etc.


The new M5 was supplied with Tahoe 26.2 installed. The broken computer was running Sonoma 14.8. Target Disk mode was a non-starter and no success with 'Share Disk' after trying multiple cables and options.


A suitable external disk was available so running the broken one clamshell closed connected to an external screen, keyboard & mouse I took a Time Machine backup. Whilst that was in progress I decided to save a little time by updating the new one to Golden Gate 26.2.


BIG mistake.


After the backup was finished I fired up Migration Assistant on the M5 and connected the Time Machine backup. after 'Searching for other Sources' for 30 or so minutes I quit from Migration Assistant.


The backup disk was showing on the desktop with the correct icon for a Time Machine disk but when it was opened the window was empty although the status bar was showing that there was the correct amount of space used for the backup.


Tried all options I could think of, Disk Utility First Aid etc., etc. all with no success.


Finally I updated the OS on the M1 computer to Golden Gate 26.2, encouraged its Time Machine to run another backup and then used that as the Source for Migration Assistant to move the data onto the M5.


A job that should've taken no more than 90 minutes ended up taking over 5 hours!


I now have a niggling thought in the back of my mind, "Would Migration Assistant in Tahoe have behaved the same?"


Chris • MacService Group • Antibes

Posted on Oct 28, 2026 3:12 AM

2 replies

steve626
User level: Level 7 (20,243 points)

Oct 28, 2026 11:17 AM in response to yugcameht

I don't understand what went wrong for you as I just did a migration from


  • iMac M1 running Sonoma


to


  • brand new M5 Macbook Air 13" running Tahoe 26.2


It sounds like what you tried initially.


I used an external Time Machine backup to do this migration. It took about 20 minutes and worked smoothly. I have done these sorts of migrations dozens of times, always with external drives with Time Machine backups (never connecting two Macs directly) and have never had an issue. I might speculate that there was something unusual or incompatible with the old Mac's configuration.


I guess all's well that ends well.

leroydouglas
User level: Level 10 (208,430 points)

Oct 28, 2026 9:52 AM in response to yugcameht

yugcameht wrote:
A job that should've taken no more than 90 minutes ended up taking over 5 hours!
I now have a niggling thought in the back of my mind, "Would Migration Assistant in Tahoe have behaved the same?"



Sounds like you got it sorted yugcameh— good computing.


Very hard to speculate on your query.

Originally posted at discussions.apple.com/thread/256384470