Specific Instruction to Downgrade MacOS Mojave Safely

Here we show step by step with screenshots How to Downgrade MacOS 10.14 Mojave back to High Sierra without loosing Data.

I was not happy at all with the new MacOS Mojave installed on my MacBook Pro – Mid 2014. This new MacOS 10.14 would be improved much in the forth-coming updates since it does slow down my Mac now. Below is how I downgraded Mojave and stay along with the previous version, High Sierra. My Data was not lost since I got a back-up with Time Machine Backup already.

Downgrade MacOS Mojave – How?

Step 1: Backup your Mac.

There are several ways to get a Backup for your current Data safe. You may want to take a look here.

Step 2: Prepare a new installation tool of High Sierra.

It’s pretty simple and easy to create an bootable USB of High Sierra installation.

  • Download the original High Sierra installation from here.
  • Create a Bootable installation USB of it by this tutorial.

Step 3: Remove the Current MacOS Mojave

  • Get your Mac connected to Internet
  • Restart your Mac from MacOS Mojave screen.

  • Keep holding down the Command+R until get into the Recovery Mode, then call the Disk Utility in the OS X Utilities selector.

Disk Utility from Recover Mode

  • Choose the MacOS Mojave Startup Disk, Click on Erase button.

Remove Mojave startup disk

  • Type the name for the file to be removed (Make it like macOS Mojave or whatever you want). Select Mac OS Extended (Journaled) from the format list if your Mac is using HFS+. At for APFS, select APFS. Make sure you Select GUID Partition Map if Scheme is available. Finally click on the Erase button.

After all, quit the Disk Utility to get back to OS X Utilities selector screen.

Step 4: Install a New-Clear MacOS High Sierra

  • Plugin the Bootable USB of High Sierra installation made from step 1 into the Mac.
  • Restart your Mac (click on Apple icon > Restart)
  • Hold the Option key while rebooting to get to Startup Disk Option.
  • Choose the Bootable High Sierra Installation Disk, and then start install the High Sierra into your Mac.

High Serra Startup Disk

It then will takes about 30 minutes to finish the whole installation processes.

Step 5: Restore Data and Setting from the Backup of the Previous High Sierra using Time Machine Backup

From the new-fresh MacOS High Sierra screen, restart your Mac. Keep hold down Command+R to go to Recover Mode > Select Restore from Time Machine Backup in the OS X Utilities selector.

  • Click on Continue > Choose your Backup source for where the Time Machine backup is stored
  • Continue > Choose the most recent macOS High Sierra backup > Continue.

You then will get all Data Back after Downgrading from Mojave to High Sierra.

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