I currently want to downgrade from macOS Monterey to Catalina 10.15.7. I have the "Install macOS Catalina" ready, I also have a 8 gb USB.
So if I boot up the USB and press install macOS Catalina will it erase everything on my disk?
btw I have time machine.
MacBook Pro 13″, macOS 12.4
maxyLYJ wrote:
I want to downgrade because I was just test using Monterey for a couple of months. I think I like macOS Catalina best.
But why from this apple webpage How to reinstall macOS - Apple Support says that i won't loose any data if i just boot from the USB?
I believe that that article is about reinstalling the same OS - specifically reinstalling Monterey when Monterey was already installed.
When you install an OS since Catalina, there are two main volumes - the system and data volumes - and a few other that are hidden. The user does not have to deal with them, but they are crucial.
Catalina is older than Monterey, and since macOS Big Sur there have been changes in how those several hidden volumes are organized. Catalina cannot be aware of stuff that did not exist at the time.
Hence to downgrade, you have to completely erase the drive and then let the installer create the proper structure for Catalina.
Anyway, even if you were just reinstalling, you should always keep an up to date backup (Time Machine is by far the easiest way to do it, but there are other options). It is usually when one does not have a backup that bad things happen...
maxyLYJ wrote:
I want to downgrade because I was just test using Monterey for a couple of months. I think I like macOS Catalina best.
But why from this apple webpage How to reinstall macOS - Apple Support says that i won't loose any data if i just boot from the USB?
I believe that that article is about reinstalling the same OS - specifically reinstalling Monterey when Monterey was already installed.
When you install an OS since Catalina, there are two main volumes - the system and data volumes - and a few other that are hidden. The user does not have to deal with them, but they are crucial.
Catalina is older than Monterey, and since macOS Big Sur there have been changes in how those several hidden volumes are organized. Catalina cannot be aware of stuff that did not exist at the time.
Hence to downgrade, you have to completely erase the drive and then let the installer create the proper structure for Catalina.
Anyway, even if you were just reinstalling, you should always keep an up to date backup (Time Machine is by far the easiest way to do it, but there are other options). It is usually when one does not have a backup that bad things happen...
I want to downgrade because I was just test using Monterey for a couple of months. I think I like macOS Catalina best.
But why from this apple webpage How to reinstall macOS - Apple Support says that i won't loose any data if i just boot from the USB?
You will have to start from the installer disk, run Disk Utility and completely erase the internal drive first, then install Catalina.
But I have to ask: why?
Downgrading macOS
