Dec 26, 2017 If you booted from a functioning recovery partition, click the “Reinstall macOS” button. The installation process will begin. If you booted from an USB disk, click “Continue” to advance to the installer. You’ll be asked which hard drive you want to install to. Installing macOS on a USB Drive 1. Format your USB drive as APFS or JHFS+. Choose the GUID Partition Table or GPT as your partition table. Connect the external hard drive to your Mac. Launch Disk Utility (press Cmd + spacebar and start to type Disk Utility). Before this next step - if you are running High Sierra or later you will need. I've already backed up my important files I want to keep to a USB.-I've tried numerous troubleshooting forums and suggestions but because of the failing hard drive I'm unable to clone my files, unable to download the applicable OS from the App Store, nothing. The only option I have is to get the current hard drive out of there. Jan 10, 2020 If you have multiple USB drives connected, then the Startup Manager shall list the drives with the bootable OS. So, this is how to boot Mac from USB drive. Part 2: Common Problems and Fixes When Boot Mac from External Drive. You may face several issues during MacBook Pro Boot from USB or any external drive.
A USB 3.0 8GB Flash Drive; An external hard drive or SSD with a USB 3.0 connector/enclosure (see the above picture) A Mac computer/Macbook or access to Hackintosh PC; TheEFI folder with right config.plist file; Patience (sometimes a lot) Before You Begin. Make sure the external hard drive or SSD does not contain any data as we will be. Connect the external drive to your Mac, and make a note of the external drive's name as it appears within macOS. This is important, as using the wrong name could lead to another connected drive.
Those who still rely on older Mac OS X operating systems, know these still are going strong. There are so many things you can do with past OS X — like Lion, Mavericks or Yosemite — each one of these operates flawlessly. So if you’re looking to give your Mac a fresh start with just a classic Mac OS X and nothing else, to clean install Mac OS from USB is the best option for you.
To clean install Mac OS from USB, there are three things you should do. First, you should clean up your Mac from the old baggage — system files that have piled up over time. Once it’s all cleaned up, the next you should do is backup your newly cleaned Mac. And finally, after doing a backup, you can clean install OS X of your choice from USB.
We’ve got the steps outlined below, so let’s get to it.
Step 1: Clean system junk on your current Mac OS X
Whatever OS X you are currently on, system junk and outdated cache files are a potential source for software conflicts. Having cleaned them up, you may discover around 35 GB of newly created space previously taken by junk. What's more, old caches may interfere with your new Mac OS X installation, so this step is pretty essential.
New Hard Drive Os Install
Cleaning can be done either manually or using a dedicated app. If you don’t want to spend the next 20 minutes on repetitive clicking and typing, jump right to the automatic solution further down.
The manual way to remove old user caches:
- Click on a Finder window and choose “Go to Folder” in the Go menu.
- Type in ~/Library/Caches and click Enter to go open the folder.
- Go through each of the folders and remove their contents.
Note: Do not remove the folders themselves, just their insides.
Next off, do the same steps, but now replace...
~/Library/Caches with… /Library/Caches
Automatic solution for system junk cleanup
There are many nice apps that offer a quick Mac clean up. Among those, CleanMyMac 3 is our favorite as it looks most user-friendly of all. It scans your hard drive for old caches, broken apps, and app leftovers so you can remove all unwanted files in a minute or two. After all, a newly installed OS X feels better on a clean computer.
Download CleanMyMac and then follow the steps:
- Launch CleanMyMac 3.
- Click Scan.
- Click Remove.
And you’re done. If you want to clean up more junk on your Mac, go through each of the modules located on the left panel of the app. It’ll help you clear out gigabytes of junk that you probably didn’t even realize were there. Once you’ve finished the cleanup, head to the next step.
Step 2: Back up your Mac
Before you begin to reinstall Mac OS from USB, you should back up your Mac. Note: If you don’t do this step, you will not be able to recover files, nor restore anything if something goes wrong. To back up your Mac:
- Open an app called Time Machine.
- Click “Select Disk.”
- Select where you wish to save your files (an external drive works best, Apple Time Capsule is a safe bet).
- Click “On” on the left-hand side of the screen to turn Time Machine on.
- On the right, under the name of the storage device, there are three lines that say, “Oldest backup,” “Latest backup,” and “Next backup.” Your backup should be scheduled within the next 5 minutes.
- Don’t want to wait? In the menu bar at the top of your screen, a few icons left of the Date & Time, click on the “arrow clock” icon and select “Back Up Now.”
Step 3: Installing Mac OS from USB
You will need 3 essential things:
- The OS X Installer (downloaded from the App Store)
- The backup of your old system
- Startup drive to install OS X on
Once it’s all prepared, it’s time to clean install OS X. But first, you need to create a bootable drive using a USB containing Mac OS X of your choice. Don’t know how? Then read on.
How to create a bootable USB flash drive
1. Connect your Mac to the USB flash drive. It should have at least 12 GB of available storage.
2. Open Terminal from the Utilities folder of your Applications folder.
3. Type or paste the following commands in Terminal:
Mavericks:
Yosemite:
El Capitan:
4. Press Return.
5. Type your administrator password and press Return.
6. When prompted, type Y to confirm that you want to erase the volume and press Return. You'll see the progress as the bootable installer is created.
7. Quit Terminal when the process is finished.
How to install the OS from USB
1. Plug in your bootable USB drive and Restart your Mac while holding the Option key. Make sure to keep it pressed down!
2. When it restarts, you’ll have a few options. Choose your USB Installer.
3. Next, select the Disk Utility option.
4. In the window, at the top of the left bar, select your Mac’s Main Drive.
5. Next, to the First Aid button at the top, click the Erase button.
6. Now, near the center of the window, select the Format drop-down list and select “Mac OS X Extended (Journaled)” as the type.
7. Click Erase (this will erase your main drive) and allow time for the drive to format.
8. When it’s finished, close out DiskUtility and select “Install OS X” from the menu.
9. Select your main drive and install a new OS X on it.
Follow the installation prompts and enjoy your new operating system. And if you want your new OS works smoothly for a long time to come, use a great cleaning and maintenance tool we've mentioned above — CleanMyMac 3. The app will take care of your Mac, so you'll get the most out of your computer again. Try it now!
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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
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.
Install Mac Os From Bootable Usb
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.
Install Mac Os From Flash Drive
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.