Time Machine won’t restore to a new disk
I’ve just restored my Late 2012 (Yosemite) iMac. I was asked to restore from Time Machine, but I opted not to do this because I wanted to restore certain folders only, so I decided to reinstall the OS instead. After a few days, I noticed Time Machine had done a few backups, but now it won’t let me view nor restore any of my files from before my system restore. Time Machine says it has 41.9MB free of 1TB, so my data is still on there! Darren Critchley It’s on there, but Time Machine isn’t showing it because it thinks it belongs to a different Mac. Every disk volume has a unique number associated with it (a UUID). Time Machine separates backups according to the UUID of the source disk, and it only shows you backups that belong to the same UUID (otherwise you’d end up with a mess of files from two different disks getting merged in the same folder). When you deleted your old volume, you created a new one with a different UUID. In future, use Migration Assistant: this relaxes the UUID constraint, so that you can restore from one Mac to another. By skipping this step, Time Machine thought it was looking at a new Mac and created a new backup set. To get to your old data back, use the tmutil command in Terminal. First find the newest snapshot of the old backup set; click Go > Network in Finder and select your Time Capsule. Click the volume that appears. This shows the sparse bundle for Time Machine. Double-click this and ‘Time Machine Backup’ will appear in the Finder sidebar. When clicked, you’ll see a folder called Backups.backupdb. Inside that is a folder for the old backup set and one for the new set.
Open Terminal and type sudo tmutil associatedisk -a / (with a space after ‘/’). Don’t hit ® ; in Finder, drag the folder for the most recent backup from the old set to the Terminal window. This will fill in the folder path to the tmutil command. Now hit ® . Your current disk UUID is now associated with the old backups and you can restore your data from Time Machine.