Time Machine OS Query

[snerkler]

I upgraded my MBP from the touchbar intel one to the newer M1 Max version and I now want to backdate the older MBP from Catalina to Mojave in order to use some older software that doesn't work on the 64 bit OS. I have a time machine backup disc but I don't think I have any old enough that will have Mojave on but is there any way to check please? Also, I have an old time machine backup disc that I had for the 27" iMac I had several years ago, can I restore the MBP from the iMac backup if that has Mojave on?

Any help would be appreciated.

 

[chabig]

Time Machine doesn't back up the operating system, just personal data. So you could reinstall Mojave from scratch and then try to restore your data from Time Machine. Some app data may not be back compatible to Mojave. You have nothing to lose in trying, though.

 

[snerkler]

Time Machine doesn't back up the operating system, just personal data. So you could reinstall Mojave from scratch and then try to restore your data from Time Machine. Some app data may not be back compatible to Mojave. You have nothing to lose in trying, though.

Thanks for the info, I always thought you could back date the OS by reinstalling an old time machine. I'll look into how to reinstall Mojave as I don't need anything from the old backup as everything's on the new MBP 👍🏻

 

[chabig]

You can get the Mojave installer here:

‎macOS Mojave

‎MacOS Mojave delivers new features inspired by its most powerful users, but designed for everyone. Stay focused on your work using Dark Mode. Organize your desktop using Stacks. Experience four new built-in apps. And discover new apps in the reimagined Mac App Store.
 Dark Mode • Experience a...

apps.apple.com

 

[snerkler]

You can get the Mojave installer here:

‎macOS Mojave

‎MacOS Mojave delivers new features inspired by its most powerful users, but designed for everyone. Stay focused on your work using Dark Mode. Organize your desktop using Stacks. Experience four new built-in apps. And discover new apps in the reimagined Mac App Store.
 Dark Mode • Experience a...

apps.apple.com

Great, thanks very much.

 

[Weaselboy]

Thanks for the info, I always thought you could back date the OS by reinstalling an old time machine.

It did up until Catalina when they switched to having separate OS and Data volumes.

 

[bernuli]

I upgraded my MBP from the touchbar intel one to the newer M1 Max version and I now want to backdate the older MBP from Catalina to Mojave in order to use some older software that doesn't work on the 64 bit OS. I have a time machine backup disc but I don't think I have any old enough that will have Mojave on but is there any way to check please? Also, I have an old time machine backup disc that I had for the 27" iMac I had several years ago, can I restore the MBP from the iMac backup if that has Mojave on?

Any help would be appreciated.

You can determine the OS version looking at the text file /System/Library/CoreServices/SystemVersion.plist.

Since this file gets backed up by Time Machine you could use the following command to find a backup set with Mojave. Change the items in all caps to be specific to your machine.

find /Volumes/NAME_OF_YOUR_BACKUP_DRIVE/Backups.backupdb/NAME_OF_YOUR_MACHINE/*/NAME_OF_YOUR_BOOT_DRIVE/System/Library/CoreServices/SystemVersion.plist -print -exec /usr/libexec/PlistBuddy -c "print ProductVersion" {} \;

You could also just change the items in all caps to be a single asterisk:

find /Volumes/*/Backups.backupdb/*/*/*/System/Library/CoreServices/SystemVersion.plist -print -exec /usr/libexec/PlistBuddy -c "print ProductVersion" {} \;

Or you could just sort through your backups manually and open the file in a text editor.

Catalina still backs up the OS.

 

[snerkler]

You can determine the OS version looking at the text file /System/Library/CoreServices/SystemVersion.plist.

Since this file gets backed up by Time Machine you could use the following command to find a backup set with Mojave. Change the items in all caps to be specific to your machine.

find /Volumes/NAME_OF_YOUR_BACKUP_DRIVE/Backups.backupdb/NAME_OF_YOUR_MACHINE/*/NAME_OF_YOUR_BOOT_DRIVE/System/Library/CoreServices/SystemVersion.plist -print -exec /usr/libexec/PlistBuddy -c "print ProductVersion" {} \;

You could also just change the items in all caps to be a single asterisk:

find /Volumes/*/Backups.backupdb/*/*/*/System/Library/CoreServices/SystemVersion.plist -print -exec /usr/libexec/PlistBuddy -c "print ProductVersion" {} \;

Or you could just sort through your backups manually and open the file in a text editor.

Catalina still backs up the OS.

Thanks very much

 

[snerkler]

Thanks for all the help, Mojave successfully installed on my old MBP 👍🏻