If you have installed the beta version of macOS 10.15 Catalina and you do not want to continue running that version on your computer, but you want to change it for one of the stable versions prior to that, you can do with these simple steps.
First we must ensure that we have a backup from Time Machine , the backup software to make backups introduced by Apple since version MacOS version 10.5, prior to installing the beta version of Catalina.
From Catalina to any version of macOS
1. We connect the Time Machine unit to the Mac, this unit must contain the previous macOS system backup .
2. Restart the M ac and immediately after restarting, press the key combination Command + R , which will start the Mac in Recovery Mode .
3. At this point, and from the ‘ macOS Utilities ‘ screen, we select the ‘ Disk Utility ‘ option.
4. Then, we select the disk with macOS Catalina beta and click on the ‘Delete’ button . We assign a name to the unit that will be removed, and select the file system format that will be called ‘ Apple File System (APFS) ‘ for MacOS Mojave or ‘ Mac OS Journal Journal (HFS +) ‘ for MacOS Sierra and Mac Older.
5. When we finish with this configuration we just have to click on ‘Delete’ to format the Ma c.
6. Then, that the process has been completed we left the Disk Utility .
7. Back on the MacOS Utilities screen , now choose the option ” Restore from the Time Machine backup “
8. Now we do the restore, choose the drive Time Machine as a source of backup and press the option ‘Continue’.
9. Then, ‘ Select a backup copy ‘ of Time Machine, and choose the most recent backup , that is, the version that we want to revert (MacOS Mojave 10.14, High Sierra 10.13, Sierra 10.12, El Capitán 10.11, among others) and we select ‘Continue’.
10. Now we select the name of the destination unit to restore the Time Machine backup which must be the same unit that was formatted in step 7, then click on ‘Restore’.
This restoration process can take a while depending on the speed of the unitsand the Mac, and after finishing the restoration the Mac will automatically restart and start in the recovered version .
It is important to note that if we do not have the backup copy of Time Machine before installing the beta version of macOS Catalina, this approach will not help us , as it will not restore the previous version.
Also Read: How to install new Windows 10 update