Catalina downgrade to mountain lion

I have been fighting to downgrade my MacBook Pro 2012 to mountain lion. I accidentally let it update to catilina so I’ve lost my ability to use some of my old programs. I struggled to create the bootable usb according to all the videos online (ended up using super duper to create one) now when i boot with option I get into the mountain lion installer I can’t see my hard drive I only have the option to install to the the usb which won’t work either

MacBook Pro 13″, macOS 10.15

Posted on Jan 5, 2023 06:58 AM

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Question marked as Top-ranking reply

Posted on Jan 7, 2023 03:13 PM

Hi kane120,


It seems you're having trouble installing an older version of macOS on your MacBook Pro and we want to help.


Your older installer won't be able to read a hard drive formatted in the newer APFS that didn't exist at the time.


You'll need to launch the Disk Utility and format the internal drive to Mac OS Extended (Journaled.)


You can follow the steps posted here:

1. Start up from macOS Recovery: Turn on your Mac, then immediately press and hold these two keys until you see an Apple logo or other image: Command (⌘) and R. 
2. If asked, select a user you know the password for, then enter their administrator password. 
3. From the utilities window, select Disk Utility and click Continue.
macOS Recovery utilities window with Disk Utility selected

4. Select Macintosh HD in the sidebar of Disk Utility. Don't see Macintosh HD?
5. Click the Erase button in the toolbar, then enter the requested details:
Name: Macintosh HD
Format: APFS or Mac OS Extended (Journaled), as recommended by Disk Utility
6. Click Erase Volume Group. If this button isn't shown, click Erase instead.
Disk Utility window showing Erase volume group confirmation

7. If asked, enter your Apple ID. Forgot your Apple ID?
8. Optional: If you previously used Disk Utility to add internal volumes other than Macintosh HD, you can erase them individually using the same process. 
9. When done, quit Disk Utility to return to the utilities window.
10. If you want your Mac to start up again from the volume you just you erased, select Reinstall macOS in the utilities window, then click Continue and follow the onscreen instructions. Learn more about reinstalling macOS.

Use Disk Utility to erase an Intel-based Mac


That should help you get this formatted correctly.


Thanks for using the Apple Support Communities.

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1 reply
Question marked as Top-ranking reply

Jan 7, 2023 03:13 PM in response to kane120

Hi kane120,


It seems you're having trouble installing an older version of macOS on your MacBook Pro and we want to help.


Your older installer won't be able to read a hard drive formatted in the newer APFS that didn't exist at the time.


You'll need to launch the Disk Utility and format the internal drive to Mac OS Extended (Journaled.)


You can follow the steps posted here:

1. Start up from macOS Recovery: Turn on your Mac, then immediately press and hold these two keys until you see an Apple logo or other image: Command (⌘) and R. 
2. If asked, select a user you know the password for, then enter their administrator password. 
3. From the utilities window, select Disk Utility and click Continue.
macOS Recovery utilities window with Disk Utility selected

4. Select Macintosh HD in the sidebar of Disk Utility. Don't see Macintosh HD?
5. Click the Erase button in the toolbar, then enter the requested details:
Name: Macintosh HD
Format: APFS or Mac OS Extended (Journaled), as recommended by Disk Utility
6. Click Erase Volume Group. If this button isn't shown, click Erase instead.
Disk Utility window showing Erase volume group confirmation

7. If asked, enter your Apple ID. Forgot your Apple ID?
8. Optional: If you previously used Disk Utility to add internal volumes other than Macintosh HD, you can erase them individually using the same process. 
9. When done, quit Disk Utility to return to the utilities window.
10. If you want your Mac to start up again from the volume you just you erased, select Reinstall macOS in the utilities window, then click Continue and follow the onscreen instructions. Learn more about reinstalling macOS.

Use Disk Utility to erase an Intel-based Mac


That should help you get this formatted correctly.


Thanks for using the Apple Support Communities.

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

Catalina downgrade to mountain lion

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