macOS Catalina

macOS Catalina is the next major operating system for Mac and launches this fall. The beta is now available for those willing to take the risk. If, after you've taken the risk, you decide it just wasn't worth it, you can downgrade back to macOS Mojave. If you follow these steps you'll be back to your old setup in no time.

Note: If you are reading this article on the Mac that you want to downgrade on, switch to another device or print this page before continuing so you can read along as you go.

Apple occasionally offers updates to iOS, watchOS, tvOS, and macOS as closed developer previews or public betas for iPhone, iPad, Apple TV and Mac (sadly, no public beta for the Apple Watch). While the betas contain new features, they also contain pre-release bugs that can prevent the normal use of your iPhone, iPad, Apple Watch, Apple TV, or Mac, and are not intended for everyday use on a primary device. That's why we strongly recommend staying away from developer previews unless you need them for software development, and using the public betas with caution. If you depend on your devices, wait for the final release.

Important information for Macs with the T2 security chip

Before you try to use a bootable installer on your Mac if you have a 2018 or newer MacBook Pro, MacBook Air, or Mac mini, you may need to make sure to allow booting from external media before you attempt to downgrade. If you've enabled the Startup Security Utility, check to make sure you'll be able to use a bootable external drive. Here's how.

Note: You'll need the firmware password you used to enable the Startup Security Utility. This is different from your administrative password and your Apple ID. Make sure you know the correct password to access the Startup Security Utility before you begin.

  1. Restart your Mac.
  2. Hold down Command+R right when you see the Apple Logo. This will put your Mac into Recovery Mode.
  3. Click Utilities in the Menu Bar.
  4. Click on Startup Security Utility.

    In Recovery Mode, click on Utilities, then select Startup Security Utility

  5. Enter your Administrator credentials.
  6. Tick the box to Allow booting from external media.

    Tick the box for Allow booting from external media

Step 1: Back up your Mac

This process will erase macOS Catalina from your hard drive entirely. That means any files, programs, or documents you've been working on while using macOS Catalina will also be erased if you don't back them up first. Use an external hard drive or a cloud-based program like DropBox, OneDrive, or iCloud. If you don't save these important files somewhere off of your computer you will lose them.

Step 2: Create a bootable drive of macOS Mojave

Before you erase macOS Catalina from your computer, download macOS Mojave from the Mac App Store. You'll need a copy of macOS Mojave on an external hard drive in order to downgrade from macOS Catalina.

Follow the steps linked below to make a bootable installer drive for macOS Mojave.

Note: Making a bootable installer requires the use of Terminal. If you don't feel comfortable making changes to your Mac with Terminal, you can create a bootable disk using the DiskMaker X program.

Step 3: Erase macOS Catalina

You'll need to erase your hard drive before re-inistalling Mojave. Remember, back up your Mac before performing this step.

  1. Connect your Mac to the internet via Wi-Fi or Ethernet.
  2. Click on the Apple icon in the upper left corner of the screen.
  3. Select Restart from the drop-down menu.

    Restarting Mac

  4. Hold down Command+R, and keep holding the keys until your computer reboots. This will put your computer into Recovery Mode.
  5. Click on Disk Utility in the OS X Utilities selector.
  6. Click Continue.

    Seleting Disk Utilities from the OS X Utilities Selector

  7. Select your Startup Disk.
  8. Click on the Erase tab at the top of the window.

    Selecting a drive to erase on Mac

  9. Enter a name for the file to be destroyed (Like macOS Catalina or something).
  10. If your Mac is using HFS+, select Mac OS Extended (Journaled) from the format list. If your Mac is using APFS, select APFS from the format list.
  11. If Scheme is available, select GUID Partition Map.
  12. Click Erase.

    Erasing a drive on Mac

After the process is complete, quit Disk Utility from the drop-down menu in the upper left corner of the screen to go back to the OS X Utilities selector.

Step 4: Reinstall macOS Mojave

After you have erased macOS Catalina, you will want to reinstall Mojave.

NOTE: If your Mac came with macOS Mojave, you can restart your Mac while holding down Shift-Option-Command-R to simply install the operating system that came with your Mac. Otherwise, follow the steps below to install Mojave back on your Mac.

  1. Connect your Mac to the internet via Wi-Fi or Ethernet.
  2. Plug the bootable hard drive you made with Mojave on it into your Mac.
  3. Click on the Apple icon in the upper left corner of the screen.
  4. Select Restart from the drop-down menu.

    Restarting Mac

  5. Hold down Option while your computer restarts. This will send you to the option to select a startup disk.
  6. Select your bootable drive with macOS Mojave from the list of startup disk options. macOS Mojave will begin installing on your Mac.
  7. Click Continue in the macOS Mojave installation window.

macOS Mojave will install like a standard update. You will agree to the licensing terms before the software reboots on your Mac.

Step 5: Restore settings from an earlier macOS Mojave Time machine backup

If you have a recent backup of your Mac saved via Time Machine (which you should), you can use it to reinstall the settings you have saved from macOS Mojave.

  1. Connect your Mac to the internet via Wi-Fi or Ethernet
  2. Click on the Apple icon.
  3. Select Restart from the drop-down menu.

    Restarting Mac

  4. Hold down Command+R when you hear the startup chime and keep holding the keys until your computer reboots.
  5. Select Restore from Time Machine Backup in the OS X Utilities selector.
  6. Click Continue.

    Selecting restore from backup from the OS X Utilities Selector

  7. Click Continue after reading the important information about restoring from a backup.
  8. Select the Backup source for where your Time Machine backup is stored.
  9. Click Continue.
  10. Select the most recent macOS Mojave backup on the drive.
  11. Click Continue.

    Steps to restore from backup on Mac

Your Mac will begin restoring from the Time Machine backup and then reboot. This process can take a while, so grab a cup of coffee while you wait.

If you run into any problems while trying to downgrade your Mac operating system, let us know in the comments.

Updated June 2019: Updated for the public beta of macOS Catalina and added steps for Macs with a T2 chip.

Some things you may need for the public beta of macOS

Samsung T5 SSD (From $85 at Amazon)

Samsung's T5 SSD has super fast transfer rates with write speeds up to 540MB/s, which is great for backing up your Mac before installing a beta.

Belkin Thunderbolt 3 cable ($30 at Amazon)

For up to four times transfer speed, make sure you're using a Thunderbolt 3 cable. Belkin's brand supports up to 100W power delivery and measures 1.6-feet long for a little extra length.

SanDisk Dual Drive (From $25 at Apple)

If you want to make a bootable installer of a new macOS or just want to preserve an older macOS in case you want to downgrade, SanDisk's Dual drive is perfect. It has a reversible USB-C and USB-A connector, too!

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