Mac Os High Sierra Won't Unmount External Drive

Oct 02, 2017 After you have made the High Sierra bootable installer, you can proceed with the next step of formatting the hard drive. 3: Format & Erase the Mac Hard Drive. With the MacOS High Sierra boot drive connected to the Mac, reboot the computer and hold down the OPTION / ALT key until you see the Startup Manager screen. At the boot drive selection.

Mac Os High Sierra Won't Unmount External Drive File
Mac Os High Sierra Won't Unmount External Drive Windows 7

These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.

To boot from your external Sierra drive, plug it into the Mac in question, press the power button, and hold the “Option key until the recovery disk screen appears. From there, you can select your external drive and click the arrow to boot into it for that session. You’ll boot into your macOS Sierra installation where you can use it as normal. Dec 26, 2017 I've had problems too with my external. I'm using a new 2017 iMac with SSD now on APFS, and always have an external drive connected - standard format (MacOS extended journaled). Since updating to High Sierra it has randomly been switching the external to 'read only' mode. Once or twice a day. I only realize it once I try to write a file and can't.

Download macOS

Find the appropriate download link in the upgrade instructions for each macOS version:

Jan 21, 2020 Mac mini introduced in mid 2010 or later iMac introduced in late 2009 or later Mac Pro introduced in mid 2010 or later. To find your Mac model, memory, storage space and macOS version, choose About This Mac from the Apple menu. If your Mac isn’t compatible with macOS High Sierra, the installer will let you know. Download and install iBoysoft Data Recovery for Mac on Mac. Launch this program. Select the unmountable WD external hard drive and click 'Next'. The program will start scanning this drive for recoverable files. After the scanning process finishes, you can click the found files and preview. I’ve written quite a bit about the not-quite-so-new Apple File System (APFS) format that Apple adopted for both iOS and—with macOS 10.13 High Sierra—for SSDs that are a Mac's boot volume. The recent Western Digital 'easy store' and 'My Book' hard drives have a Mac Sierra 10.12.6 issue: They are invisible to the Desktop. WD Utilities says my two drives check out ok; Mac Utilities recognizes both hard drives. Going to the Mac Genius Bar on Monday. BestBuy sold me the original WD easystore 8T and WD sent me a My Book 8T.

macOS Catalina, macOS Mojave, ormacOS High Sierra
Installers for each of these macOS versions download directly to your Applications folder as an app named Install macOS Catalina, Install macOS Mojave, or Install macOS High Sierra. If the installer opens after downloading, quit it without continuing installation. Important: To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators, please download from Apple, not a locally hosted software-update server.

OS X El Capitan
El Capitan downloads as a disk image. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, not from the disk image or .pkg installer.

Use the 'createinstallmedia' command in Terminal

Connect the USB flash drive or other volume that you're using for the bootable installer. Make sure that it has at least 12GB of available storage and is formatted as Mac OS Extended.
Open Terminal, which is in the Utilities folder of your Applications folder.
Type or paste one of the following commands in Terminal. These assume that the installer is still in your Applications folder, and MyVolume is the name of the USB flash drive or other volume you're using. If it has a different name, replace MyVolume in these commands with the name of your volume.
Catalina:*
Mojave:*

High Sierra:*
El Capitan:
Press Return after typing the command.
When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the bootable installer is created.
When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Catalina. You can now quit Terminal and eject the volume.

* If your Mac is using macOS Sierra or earlier, include the --applicationpath argument, similar to the way this argument is used in the command for El Capitan.

Use the bootable installer

After creating the bootable installer, follow these steps to use it:

Plug the bootable installer into a compatible Mac.
Use Startup Manager or Startup Disk preferences to select the bootable installer as the startup disk, then start up from it. Your Mac will start up to macOS Recovery.
Learn about selecting a startup disk, including what to do if your Mac doesn't start up from it.
Choose your language, if prompted.
A bootable installer doesn't download macOS from the Internet, but it does require the Internet to get information specific to your Mac model, such as firmware updates. If you need to connect to a Wi-Fi network, use the Wi-Fi menu in the menu bar.
Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

For more information about the createinstallmedia command and the arguments that you can use with it, make sure that the macOS installer is in your Applications folder, then enter this path in Terminal:

Catalina:

Mojave:

High Sierra:

El Capitan:

Check compatibility

You can upgrade to macOS High Sierra from OS X Mountain Lion or later on any of the following Mac models. Your Mac also needs at least 2GB of memory and 14.3GB of available storage space.

MacBook introduced in late 2009 or later
MacBook Air introduced in late 2010 or later
MacBook Pro introduced in mid 2010 or later
Mac mini introduced in mid 2010 or later
iMac introduced in late 2009 or later
Mac Pro introduced in mid 2010 or later

To find your Mac model, memory, storage space and macOS version, choose About This Mac from the Apple menu . If your Mac isn’t compatible with macOS High Sierra, the installer will let you know.

Make a backup

Before installing any upgrade, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.

Get connected

It takes time to download and install macOS, so make sure that you have a reliable Internet connection. If you’re using a Mac notebook computer, plug it into AC power.

Download macOS High Sierra

For the strongest security and latest features, find out whether you can upgrade to macOS Catalina, the latest version of the Mac operating system.

If you still need macOS High Sierra, use this App Store link: Get macOS High Sierra.

Begin installation

After downloading, the installer opens automatically.

Click Continue and follow the onscreen instructions. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.

If the installer asks for permission to install a helper tool, enter the administrator name and password that you use to log in to your Mac, then click Add Helper.

Allow installation to complete

Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar or show a blank screen several times as it installs both macOS and related updates to your Mac firmware.