Starting with OS X Lion, Apple did away with DVDs and other media as a method of installing software and switched to a download model instead.Even so, it's still easy to create a USB installation disk for OS X Lion if you want to install Lion on a freshly formatted hard drive, if you're in an emergency booting situation, or if you need to repair your Mac's hard drive. Set your bootable USB as your startup disk for the next boot in 'Apple Menu - System Preferences - Startup Disk,' then click 'Restart' to reboot your Mac. Your Mac will reboot from the USB instead of your default startup disk. Alternatively, you can also use the Startup Manager to select your boot drive when you start macOS.
By default, Mac starts from its built-in hard disk, but a startup disk can be any storage device that contains bootable contents that compatible with your Mac. For example, if you install macOS or Microsoft Windows on a USB drive, your Mac can recognize that drive as a startup disk. This guide provides 2 ways to boot a Mac from a USB flash drive.
Requirement
Starting up your Mac from an external disk requires the following:
- Intel-based Mac.
- Bootable USB thumb drive formatted with a GUID partition type and containing an OS X installer or a usable operating system.
Let's see how to boot a Mac from a bootable USB drive and what to do if your Mac doesn't start up from it.
Way 1: Boot Mac from USB Drive using Startup Manager
Getting your Mac to load from a USB drive is fairly straightforward. Use the following steps, you can easily set Mac boot from an external drive in Startup Manager, so it'll only boot from USB that one time.
Step 1: Insert the USB boot media into a USB slot.
Step 2: Turn on your Mac (or Restart your Mac if it's already on).
Step 3: Press and hold the Option key immediately after you see the Apple logo. Holding that key gives you access to OS X's Startup Manager. Once the Startup Manager screen appears, release the Option key. The utility will look for any available drives that include bootable content.
Step 4: Using either the pointer or arrow keys on the keyboard, select the USB drive you wish to boot from. Once selected, either hit the Return key or double-click your selection. The machine will start to boot from the USB drive.
Way 2: Set a Mac Boot from USB Drive using Startup Disk
When you use Startup Disk preferences to set Mac boot from an external drive, so it'll boot from that disk until you choose a different one. Here is how:
Step 1: Go to Apple menu > System Preference, then click Startup Disk.
Step 2: Click the locked icon and then enter your administrator password.
Step 3: Select External drive as the startup disk, then restart your Mac.
What to do if your Mac does not boot from the selected drive
If you see a message prompts that your security settings do not allow this Mac to use an external startup disk, check the External Boot setting in Startup Security Utility, and then allow your Mac to use an external startup disk.
Step 1: Open Startup Security Utility.
Turn on your Mac, then press and hold Command (⌘) + R immediately after you see the Apple logo. Your Mac starts up from macOS Recovery. When you see the macOS utility window, choose Utilities > Startup Security Utility from the menu bar. When you're asked to authenticate, click Enter macOS Password, then choose an administrator account and enter its password.
Step 2: Select 'Allow booting from external media'.
If you want to select an external startup disk before restarting your Mac, quit Startup Security Utility, then choose Apple menu > Startup Disk.
Note: If you're using Boot Camp in a dual-boot Windows/OS X environment, you may be unable to boot negatively into supported versions of Microsoft Windows XP, Windows Vista or Windows 10 operating systems installed on external USB hard drive.
Make sure disk has been formatted with a GUID partition type
Intel-based Macs support starting from an external USB storage device's volume that has been formatted with a GUID partition type. If you wish to boot from the drive, it's important to format the partition as 'GUID Partition Table' rather than either of the other two ahead of time when you use that drive as a bootable drive.
Make sure your disk is bootable
How to buy minecraft for someone. Volumes that aren't bootable and don't contain a copy of a valid operating system aren't listed in Startup Disk or Startup Manager. Make sure the external drive you're trying to start from contains a usable operating system.
Start up from macOS Recovery
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
- Apple silicon: turn on your Mac and continue to press and hold the power button until you see the startup options window, which includes a gear icon labelled Options. Select Options, then click Continue.
- Intel processor: make sure your Mac has a connection to the Internet. Then turn on your Mac and press and hold Command (⌘)-R immediately until you see an Apple logo or another image.
If you're asked to select a user you know the password for, select the user, click Next and enter their administrator password.
Reinstall macOS
How To Install Mac Os Using Usb
Select Reinstall macOS from the utilities window in macOS Recovery and then click Continue and follow the installer's instructions.
How to purchase pubg pc. Follow these guidelines during installation:
How To Install Mac Os Using Usb
- Allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac may restart and show a progress bar several times, and the screen may be empty for minutes at a time.
- If the installer asks to unlock your disk, enter the password you use to log in to your Mac.
- If the installer can't see your disk or notifies you that it can't install macOS on your computer or volume, you may need to erase your disk first.
- If the installer is for a different version of macOS to what you expected, find out about other installation options, below.
- If the installer offers you the choice between installing on Macintosh HD or Macintosh HD – Data, choose Macintosh HD.
When the installation is complete, your Mac may restart to a setup assistant. If 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 the setup process.
Other macOS installation options
By default, macOS Recovery installs the latest macOS that was previously installed on your Mac.* You can get other macOS versions using one of these methods:
- On an Intel-based Mac, you can use Option-Command-R at startup to upgrade to the latest macOS that is compatible with your Mac. Exceptions:
- If macOS Sierra 10.12.4 or later was never previously installed, you will receive the macOS that came with your Mac, or the closest version still available.
- If your Mac has the Apple T2 Security Chip and you never installed a macOS update, you will receive the latest macOS that was installed on your Mac.
- On an Intel-based Mac that used macOS Sierra 10.12.4 or later previously, you can use Shift-Option-Command-R at startup to install the macOS that came with your Mac, or the closest version still available.
- Reinstall macOS from the App Store instead of using macOS Recovery. If you can't install the latest macOS, you may be able to install an earlier macOS.
- Create a bootable installerand then use it to install macOS on your Mac or another Mac.
* If you've just had your Mac logic board replaced during a repair, macOS Recovery may only offer the latest macOS compatible with your Mac. If you erased your entire disk instead of just the startup volume on that disk, macOS Recovery may only offer the macOS that came with your Mac, or the closest version still available.
