Reinstall from macOS Recovery
macOS Recovery makes it easy to reinstall the Mac operating system, even if you need to erase your startup disk first. All you need is a connection to the Internet. If a wireless network is available, you can choose it from the Wi-Fi menu , which is also available in macOS Recovery.
1. Start up from macOS Recovery
Not only macOS High Sierra but you’ll also need a bootable USB drive to install new versions of macOS Mojave, macOS Catalina, and updated versions. A bootable flash drive is an external hard drive or optical disk that is created with a computer operating system and can be used to boot a desktop computer or laptop instead of the Windows.
To start up from macOS Recovery, turn on your Mac and immediately press and hold one of the following sets of keys on your keyboard. Release the keys when you see an Apple logo, spinning globe, or other startup screen.
Command (⌘)-R
Reinstall the latest macOS that was installed on your Mac (recommended).
Option-⌘-R
Upgrade to the latest macOS that is compatible with your Mac.
Shift-Option-⌘-R
Reinstall the macOS that came with your Mac, or the closest version still available.
You might be prompted to enter a password, such as a firmware password or the password of a user who is an administrator of this Mac. Enter the requested password to continue.
When you see the utilities window, you have started up from macOS Recovery.
2. Decide whether to erase (format) your disk
You probably don't need to erase, unless you're selling, trading in, or giving away your Mac, or you have an issue that requires you to erase. If you need to erase before installing macOS, select Disk Utility from the Utilities window, then click Continue. Learn more about when and how to erase.
3. Install macOS
When you're ready to reinstall macOS, choose Reinstall macOS from the Utilities window. Then click Continue and follow the onscreen instructions. You will be asked to choose a disk on which to install.
- If the installer asks to unlock your disk, enter the password you use to log in to your Mac.
- If the installer doesn't see your disk, or it says that it can't install on your computer or volume, you might need to erase your disk first.
- If the installer is for a different version of macOS than you expected, learn about macOS Recovery exceptions.
- If the installer offers you the choice between installing on Macintosh HD or Macintosh HD - Data, choose Macintosh HD.
Please allow installation to complete without putting your Mac to sleep or closing its lid. During installation, your Mac might restart and show a progress bar several times, and the screen might be empty for minutes at a time.
If your Mac restarts to a setup assistant, but you're selling, trading in, or giving away your Mac, press Command-Q to quit the assistant without completing setup. Then click Shut Down. When the new owner starts up the Mac, they can use their own information to complete setup.
macOS Recovery exceptions
The version of macOS offered by macOS Recovery might vary in some cases:
- If macOS Sierra 10.12.4 or later has never been installed on this Mac, Option-Command-R installs the macOS that came with your Mac, or the closest version still available. And Shift-Option-Command-R isn't available.
- If you erased your entire disk instead of just the startup volume on that disk, macOS Recovery might offer only the macOS that came with your Mac, or the closest version still available. You can upgrade to a later version afterward.
- If your Mac has the Apple T2 Security Chip and you never installed a macOS update, Option-Command-R installs the latest macOS that was installed on your Mac.
- If you just had your Mac logic board replaced during a repair, macOS Recovery might offer only the latest macOS that is compatible with your Mac.
If you can't get macOS Recovery to offer the installer you want, you might be able to use one of the other ways to install macOS.
Other ways to install macOS
- You can also install macOS from the App Store or Software Update preferences. If you can't install macOS Catalina, you might be able to install an earlier macOS, such as macOS Mojave, High Sierra, Sierra, El Capitan, or Yosemite.
- Or create a bootable installer disk, then use that disk to install macOS on your Mac or another Mac.
What’s up guys, in this tutorial I’m going to show you How to Create Bootable USB Installer for macOS High Sierra Windows 10 Operating System. There are few applications that you need to download in-order to successfully create a bootable USB Flash Drive to install macOS High Sierra Windows 10 PC.
Firstly, you need to download TransMac application as we will use this to write files onto flash drive. Once you have downloaded and installed TransMac, run the application.
TransMac is a Paid Application. But the trial period will last for 15 days, this is more than enough for us to Create Bootable USB Installer for macOS High Sierra Windows 10.
Before you click Run, just make sure you have plugged-in your 16 GB USB Flash Drive.
Now, Click Run and proceed with the trial of 15 Days. You should see the following screen once you click Run.
Right-Click on your USB Flash Drive and select the option Format Disk for Mac.
When the warning pops-up click Yes.
TransMac will now ask you to name your ISB Drive. I will name my USB Drive as “USB Installer“, but you can name it anything you like. After you Name the USB Drive click OK.
Click Yes, when TransMac will give you the Overwrite warning.
Now, just wait for few moments, as the formatting process is going on.
How To Download Macos High Sierra On Windows 10
Once the formatting is successfully completed you should get this following confirmation. If it is not a success, please follow the steps again and format your flash drive.Click Ok, and now right-click on your USB Flash Drive again and select the option Restore with Disk Image.
Click Yes, when TransMac gives you a warning for Overwriting.Next Step is to Select the dmg file for macOS High Sierra. You would need an Mac to download the macOS High Sierra Installation file from Apple Store.
To locate the DMG File, follow these steps
After you have downloaded the High Sierra app, locate the InstallESD.DMG from the installer.
In Applications folder: Right-click on Install MacOS High Sierra app, then choose Show Packages Contents to reveal Contents folder.
The MacOS High Sierra InstallESD.DMG is found under: Contents/SharedSupport/
Now copy this InstallESD.DMG as you need it in TransMac to Create macOS High Sierra Bootable USB Installer on Windows 10.
Ok, so lets continue with TransMac Restore Disk Image to Drive. On this screen, select the InstallESD.DMG file and click OK.
Click Yes, when TransMac Gives you the Overwrite warning.
Now the TransMac will start the process of Restoring High Sierra Image on the Flash Drive. this will take 15-25 minutes, depending on the speed of your flash drive.