Can you downgrade from High Sierra to Mountain Lion?

It cannot downgrade to anything less than that. I am going to guess a 2013 was Mavericks. Once you verify that, you can actually close out the reinstall process (don’t go through with it yet) and use Disk Utilities to erase your hard drive (Macintosh HD) to give yourself a clean re-install of Mountain Lion.

How do I remove High Sierra from my Mac?

Step 3: Erase macOS High Sierra

1. Connect to Time Machine.
2. Restart your Mac in Recovery Mode: press Command + R while you reboot.
3. At the macOS Utiities screen press Disk Utility.
4. Click Continue and then select Startup Disk (where OS is located)
5. Hit Erase. Choose a new disk name and select Mac OS Extended (Journaled) format.

How do I restore my Macbook Pro to Mountain Lion?

Reinstalling Mountain Lion

1. Restart your computer, and immediately hold down command-r until the gray Apple logo appears.
2. If prompted, select your main language and then click the arrow.
3. Click Reinstall OS X, and then Continue.

How do I revert back to an old Mac without time machine?

How to Downgrade macOS without Time Machine

1. Download the installer for the macOS version you want to install.
2. Once downloaded, don’t click on Install!
3. Once done, restart your Mac.
4. In Recovery mode, select “Reinstall macOS” from Utilities.
5. Once done, you should have a working copy of an older version of macOS.

How do I downgrade from High Sierra to Sierra without time machine?

How to downgrade without a Time Machine backup

1. Plug the new bootable installer into your Mac.
2. Restart your Mac, holding the Alt key and, when you see the option, choose the bootable install disk.
3. Launch Disk Utility, click on the disk with High Sierra on it (the disk, not just the volume) and click the Erase tab.

How do I downgrade my Mac?

How to downgrade to the OS that shipped on your Mac

1. Start up your Mac pressing Shift-Option/Alt-Command-R.
2. Once you see the macOS Utilities screen choose the Reinstall macOS option.
3. Click Continue and follow the on-screen instructions.
4. Select your startup disk and click Install.

Can I downgrade macOS High Sierra?

If you’re on High Sierra 10.12. 4 or later, and you want to revert to the version of macOS that shipped with your Mac, then you’re in luck! This is one of the easiest ways to downgrade your Mac: Restart your Mac, while holding down the ‘Shift+Option+Command+R’ keys.

How do I downgrade my macOS High Sierra without time machine?