Mac – How to downgrade from MacOS Catalina to Mojave

backupcatalinatime-machine

Yesterday I made a blunder of upgrading my Macbook 2015(March) from Mojave to Catalina.

Since then I am facing different issues like applications not responding, terminal crashing, etc.

Now I want to get rid of it and reinstall Mojave. I know I do not have CD of it and I will take all necessary data backup. I do not have TimeMachine backup either. What can I do to downgrade?

Issues Images:

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Best Answer

Before you begin

The first thing to understand is that downgrading means you'll need to:

  • erase your MacBook's drive, and since you don't have a Time Machine backup you'll need to make one (or back up your data in some other way), before downgrading
  • have an external drive that you can totally erase as part of the process.

Downgrading from Catalina to Mojave

To downgrade, follow these steps:

  1. Use Time Machine (or some other backup method) to back up your data
  2. On your MacBook, use Safari (or another web browser) to open this link:

https://apps.apple.com/ph/app/macos-mojave/id1398502828?mt=12

  1. The Mac App Store should open up on the macOS Mojave page
  2. Download the macOS Mojave installer
  3. Connect your external drive to your MacBook

  4. Use Disk Utility to totally erase the external drive as follows:

    • leave the drive name as Untitled
    • format it as either Mac OS Extended (Journaled) or APFS
    • use the GUID Partition Map

  5. Open Terminal

  6. Enter (or copy and paste) the following command into Terminal

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled

NOTE: If at Step 6 you decided to give the external drive a different name, then replace the Untitled bit at the end of the command with whatever you called your drive

  1. Press enter
  2. When prompted enter your admin password (note you won't actually see it appear on screen)
  3. Press enter
  4. When prompted, press the Y key to confirm
  5. Press enter
  6. Terminal will start displaying what it's doing - wait until you see the Done. message
  7. Shutdown your MacBook
  8. Reboot your MacBook while holding down the option key
  9. In a short while you'll see some startup disk options
  10. Now select and boot from the external drive

(Note: your external drive name will be Install macOS Mojave as the Terminal command we used earlier automatically changed it from Untitled).

  1. Use the Disk Utility option to erase the internal drive (preferably in APFS format and making sure you use the GUID Partition Map option)
  2. Once complete, exit Disk Utility to follow the on-screen instructions to install macOS Mojave onto the internal drive of your MacBook
  3. Now use the Time Machine (or other) backup you made at Step 1 to copy across your data
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