Summary: Learn how to restore your macOS using different easy-to-follow DIY methods. You can either reinstall macOS or restore macOS from Time Machine backup. In case the restoration process fails due to power failure, backup corruption, or otherwise, recover your lost data through this free-to-try Mac data recovery software.
You need to restore macOS in the following situations—when your Mac is not working as expected and throws kernel panic error, you need to change the Mac administrator, or when you want to sell or repurpose your Mac.
To restore macOS, boot your Mac in macOS Recovery mode, then from the macOS Utilities window, choose an appropriate option (reinstall macOS or restore macOS From Time Machine Backup). The next sections describe two restoration methods in detail.
Reinstall macOS Using macOS Recovery
Steps to reinstall macOS using macOS Recovery mode are as follows:
a) Start or restart your Mac, then press and hold any one of the required keys:
Command + R keys to reinstall the latest macOS that was present on your Mac.
Option + Command + R keys to upgrade to the latest compatible macOS.
Shift + Option + Command + R keys to install the manufacturer provided or its closest macOS.
b) Release the keys when the Apple logo, spinning globe, or other startup screen appears. Choose a wireless network from the Wi-Fi menu in macOS Recovery mode.
c) Enter your Mac password or firmware password when prompted, then click Continue.
d) To erase your Mac storage drive or volume, back up your Mac beforehand. Now, in macOS Recovery mode, go to macOS Utilities, click Disk Utility, then click Continue. Select the Mac hard drive from the sidebar, click the Erase tab. Specify the Name, Format, and Scheme, then click Erase. Once drive formatting is over, quit Disk Utility.
e) Click Reinstall macOS from the macOS Utilities window, then click Continue.
f) Perform the onscreen instructions to reinstall macOS. Finally, restore data from the backup.
Restore macOS Using Time Machine Backup
When you have an up-to-date backup of your Macintosh HD through Time Machine, you can quickly restore your macOS. Steps are as follows:
a) Ensure the Time Machine backup drive is connected to your MacBook, Mac mini, or iMac.
b) Start or restart your Mac, then immediately press and hold the Command + R keys.
c) Release the keys when the Apple logo appears. Mac boots into macOS Recovery mode.
d) From macOS Utilities, select Restore From Time Machine Backup, then click Continue.
e) On the Restore Your System screen, click Continue.
f) Select the Time Machine backup disk, then click Continue.
g) Select the latest backup, then click Continue.
h) Once the restoration process completes, restart your Mac.
Recover Erased Drive’s Data Using Mac Data Recovery Software
It is rare but possible that your macOS restoration process fails. This unsuccessful restoration can happen due to any reason. Also, during macOS restoration, you may have erased your Mac without taking backup. So, you end up losing your data from your Mac due to the drive erasure.
Don’t worry. A bootable data recovery software for Mac can help you restore data from an erased Mac hard drive. Steps are as follows:
a) Download and install Stellar Data Recovery Professional software on a working Mac. Activate the software using the purchased license key.
b) Connect an empty USB Drive of at least 8 GB to the Mac. Launch the data recovery software.
c) From the main screen, go to More Tools > Create Recovery Drive. Or else, from the bottom left corner, click the Click here link beside Create Recovery Drive.
e) Insert the bootable USB flash drive into your Mac without macOS. Press the power button to start the Mac, then immediately press-hold the Option key.
f) From the startup menu, select the USB recovery drive for booting the Mac. Once the Mac boots from the USB drive, from macOS Utilities, select StellarDataRecovery and click Continue.
g) When the software launches on the erased Mac without macOS, click Next. Select Macintosh HD, turn on Deep Scan, and click Scan.
h) Preview the scanned files, select the required files, and click Recover. Click Browse to specify an external hard drive for saving the recoverable data, then click Save.
After recovering data from the Mac without macOS, reinstall macOS using macOS Recovery, as explained before. Finally, save the recovered data from the external hard drive to the Mac.
When you need to restore your macOS, you can do it easily through macOS Recovery mode. You can either reinstall macOS or restore from Time Machine backup. But, if the macOS restoration process fails, you can’t boot your Mac, and all your data turns inaccessible. Stellar Data Recovery Professional for Mac software has a Create Recovery Drivefeature.It allows you to create a bootable USB medium that can recover data from Mac without the macOS.