re-use old backup after restore

[msvadi]

I recently had to restore my data from a Time Machine Backup. Before restoring, I erased the disk, re-installed the OS, and imported from the backup only user data using the Migration Assistant. When I try to use Time Machine on the computer, it wants to start a new full backup.

I'm wondering if it's possible to re-use the old backup that was used for restoring. Most of it is 1TB of user data, so it seems a bit silly not to re-use it.

Thanks

 

[KALLT]

It is possible to re-connect the backups again. Be aware that Time Machine may at some point delete old snapshots and delete the data that isn’t currently on your main disk. It thus won’t absolve you from your responsibility to make sure that the data you want to keep is on your disk.

There is a guide for this here: http://pondini.org/TM/B6.html. You will find the procedure in the large pink box titled ‘“Associate” an OSX volume’.

For the future: you should restore a complete Time Machine snapshot instead of reinstalling macOS. Both options are presented to you when you boot from Recovery. This is the best way to do it. Alternatively, if you do use Setup Assistant, make sure that you import ‘Settings’ as well. This will make sure that macOS recognises a previous Time Machine disk.

 

[msvadi]

It is possible to re-connect the backups again. Be aware that Time Machine may at some point delete old snapshots and delete the data that isn’t currently on your main disk. It thus won’t absolve you from your responsibility to make sure that the data you want to keep is on your disk.

There is a guide for this here: http://pondini.org/TM/B6.html. You will find the procedure in the large pink box titled ‘“Associate” an OSX volume’.

For the future: you should restore a complete Time Machine snapshot instead of reinstalling macOS. Both options are presented to you when you boot from Recovery. This is the best way to do it. Alternatively, if you do use Setup Assistant, make sure that you import ‘Settings’ as well. This will make sure that macOS recognises a previous Time Machine disk.

It worked, thank you.

I did not do a complete restore on purpose. It's a new Mac, and I used Migration Assistant to migrate everything from my old Mac, including settings and applications. However, most of the applications could not run and had to be reinstalled anyway, and what's worse, the system was behaving weirdly: random automatic reboots, apps crashing, troubles with waking up from sleep. I thought that migrating everything from the old Mac caused these problems, and decided to have a clean start by erasing everything and keeping only user data.