I have currently made a backup of my MacBook running with Catalina. I then reinstalled Mojave and am now trying to find out if there is a way to restore the data, which I have backed up without automatically updating back to Catalina.

Does anyone know a way to "exclude" the restoring of the OS or alternatively pre-select which parts of the Time Machine backup should be included?

Sidenote: Unfortunatelly, I lost my old backup, so I do not have a backup made shortly before I upgraded, which I could otherwise easily use.

  • 1
    Golden rule - swap out to a new TM drive before updating, or expect pain if you ever want to revert. There is never any supported 'downhill' route, so you have to make your own. You could try a Migrate from the old TM, rather than restore.
    – Tetsujin
    Oct 19, 2019 at 13:36

2 Answers 2


I did the same thing by using a USB installer and migrated data from the Time Machine backup during the install (it's one of the choices during the install). In my experience the data (minus the OS) should come back to Mojave but it may not be visible in the list of backups to choose from when choosing a backup source during the install. To explain further:

When I installed Catalina I chose to migrate data from the Time Machine backup of Mojave which was successful. In the brief period of time I had Catalina it made maybe 1 or 2 Time Machine backups. When I chose to erase the SSD, and install Mojave again, Catalina appeared to have changed the file extension of the backup from .sparsebundle to .backupbundle . This stopped Time Machine on Mojave from being able to show me the backup to select (imagine my heart rate). So, erased again, installed Catalina, and after browsing the Time Machine backup in Finder, I could see the old backup there, changed the file extension from .backupbundle to .sparsebundle , erased the SSD again, installed Mojave and presto, the previous Mojave backup was visble again. The data migrated successfully for the most part (except my Contacts which is a whole other story).

  • Thank you for the explanation and glad it worked out for you. Unfortunately, as I mentioned in my original post, I lot my old backup, so I do not have a Mojave TM backup, but only a Catalina one... I guess I will look further for some trick to solve that.
    – rvi
    Oct 20, 2019 at 9:19
  • @rvi - any luck taking a Catalina TM backup and putting it in Mojave? Feb 24, 2020 at 16:37
  • @kraftydevil Unfortunately not. I found out that it is not possible to do it in a "simple way" due to the fact that every restoring from a backup done on a newer version of an OS automatically updates the OS. The only way to do that would be to manually move all files and reinstall programs, etc. Also new Macbooks prevent you from installing a random OS. Meaning that you can go for the factory OS or the latest. I did manage to get Mojave installed in the Apple Store though... (Apologies, I must have missed your question)
    – rvi
    Aug 19, 2020 at 10:23

You can try to use the Migration Assistant app from within macOS (which you can find in the Utilities folder) and choose only specific files to restore, like your user folder etc.

This may depends on if the Catalina backup is readable by Mojave as they have different backup formats: Mojeve (.sparsebundle and Catalina .backupbundle).

See: https://support.apple.com/el-gr/HT204350.

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