Mac Os X Install Usb

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The process of installing OS X or macOS on a Mac hasn't changed a great deal since OS X Lion altered the delivery of the OS from optical disks to electronic downloads, using the Mac App Store.

The process of installing OS X or macOS on a Mac hasn't changed a great deal since OS X Lion altered the delivery of the OS from optical disks to electronic downloads, using the Mac App Store. The big advantage of downloading the Mac OS is, of course, immediate gratification (and not having to pay shipping charges). How to Install macOS From USB Choosing a USB Flash Drive for Installing Mac. Formatting Your USB Flash Drive. Downloading the macOS Installer. Creating a Bootable USB Using Terminal. Creating a Bootable USB Using DiskMaker X. Booting Your Mac From a USB Drive. Using Your Bootable macOS USB.

The big advantage of downloading the Mac OS is, of course, immediate gratification (and not having to pay shipping charges). But the downside is that the installer you download is deleted as soon as you make use of it by installing the Mac operating system.

Install

With the installer gone, you lose the opportunity to install the OS on more than one Mac without having to go through the download process again. You also lose out on having an installer that you can use to perform clean installs that completely overwrite your startup drive, or having an emergency bootable installer that includes a few useful utilities that can bail you out of an emergency.

To overcome these limitations of the installer for OS X or macOS, all you need is a USB drive that contains a bootable copy of the installer.

How to Create a Bootable Flash Installer of the OSX or MacOS on a USB Drive

There are two ways to make a bootable copy of the installer; one makes use of Terminal, the command-line utility included with all copies of OS X and macOS; the other uses a combination of the Finder, Disk Utility, and Terminal to get the job done.

In the past, we've always shown you the manual method, which uses the Finder, Disk Utility, and Terminal. Although this method involves more steps, it's easier for many Mac users because the majority of the process uses familiar tools. This time around, we're going to show you the Terminal app method, which uses a single command that has been included with the Mac OS installer since OS X Mavericks was released.

The OS X Yosemite installer is the last version of the installer with which we verified this manual method using the Finder, Disk Utility, and Terminal. The general recommendation is to skip the manual method for any version of the Mac OS that is newer than OS X Mavericks, and instead use the Terminal method and the createinstallmedia command, as outlined below.

Start by Not Starting

Before you begin, stop. That may sound a bit daft, but as we mentioned above, if you use the OS X or macOS installer, it will likely delete itself from your Mac as part of the installation process. So, if you haven't yet used the installer you downloaded, don't. If you've already installed the Mac OS, you can re-download the installer following these instructions:

If you're just now downloading the installer, you'll notice that once the download is complete, the installer will start up on its own. You can just quit the installer, the same way you'd quit any other Mac app.

What You Need

You should already have the OS X or macOS installer on your Mac. It will be located in the /Applications folder, with one of the following names:

A USB flash drive. You can use any USB drive that is 8 GB in size or larger. We suggest a flash drive in the 32 GB to 64 GB range, as they seem to be the sweet spot in cost and performance. The actual size of the bootable version of the installer varies, depending on which version of the Mac OS you're installing, but so far, none has gone over 8 GB in size.

A Mac that meets the minimum requirements for the OS you're installing:

If you have everything you need, let's get started, using the createinstallmedia command.

Use the Createinstallmedia Command to Create a Bootable Mac Installer

Mac Os X Usb Install Drive

It's not really that much of a secret, but ever since OS X Mavericks, the Mac OS installers have contained a command hidden inside the installer package that takes what used to be a complex process for creating a bootable copy of the installer, and turns it into a single command you enter into Terminal.

Mac Os X Install Usb

This Terminal command, called createinstallmedia, can create a bootable copy of the installer using any drive connected to your Mac. In this guide, we're going to use a USB flash drive, but you could also use a normal hard drive or SSD that's connected to your Mac. The process is the same, regardless of the destination. Whatever media you use to create the bootable Mac OS installer on, it will be completely erased by the createinstallmedia command, so be careful. Whether you're going to use a flash drive, a hard drive, or an SSD, be sure to back up any data on the drive before you begin this process.

How to Use the Createinstallmedia Terminal Command

  1. Make sure that the Mac OS installer file is present in your /Applications folder. If it's not there, or you're not sure of its name, seethe previous section of this guide for details on the installer file name, and how to download the needed file.
  2. Plug your USB flash drive into your Mac.
  3. Check the flash drive's content. The drive will be erased during this process, so if there's any data on the flash drive that you want to save, back it up to another location before proceeding.
  4. Change the flash drive's name to FlashInstaller. You can do this by double-clicking the drive's name to select it, and then type in the new name. You can actually use any name you wish, but it must exactly match the name you enter in the createinstallmedia command below. For this reason, we strongly suggest using a name with no spaces and no special characters. If you use FlashInstaller as the drive's name, you can just copy/paste the command line below instead of typing the rather long command into Terminal.
  5. Launch Terminal, located in /Applications/Utilities.
  6. Warning:The following command will completely erase the drive named FlashInstaller.

In the Terminal window that opens, enter one of the following commands, depending on which OS X or macOS installer you're working with. The command, which starts with the text 'sudo' and ends with the word 'nointeraction' (with no quotes), can be copy/pasted into Terminal unless you used a name other than FlashInstaller. You should be able to triple-click the command line below to select the entire command.​
macOS High Sierra Installer Command Line

  1. Copy the command, paste it into Terminal, and then press the return or enter key.
  2. You'll be asked for your administrator password. Enter the password and press return or enter.
  3. The terminal will execute the command. It will first erase the destination drive, in this case, your USB flash drive named FlashInstaller. It will then begin copying all of the needed files. This process can take some time, so be patient, have some yogurt and blueberries (or your snack of choice); that should just about match the amount of time needed to complete the copying process. Of course, the speed is dependent on the device you're copying to.
  4. When the process is complete, Terminal will display the line Done, and then display the Terminal command prompt line.

You now have a bootable copy of the OS X or macOS installer that you can use to install the Mac OS on any of your Macs, including using the advanced Clean Install method; you can also use it as a troubleshooting utility.

Is it time to sell or give away your old Mac? Or do you just want a fresh start to clean up your machine? Here’s how to securely delete all of your files, then install a fresh version of macOS.

If you’re selling or giving away your computer, this is the only way to make sure whoever ends up with your Mac can’t access to your files, and won’t have to deal with any modifications you’ve made to macOS over the years. Don’t just delete your user profile and call it a day—you’ll want to completely wipe it.

Before you start, make sure you transfer any files you want to keep to a new computer or external drive. Even if you don’t intend on wiping your drive, it’s a good idea to back up before re-installing your operating system.

Step One: Boot From Recovery Mode, or an Installer

RELATED:8 Mac System Features You Can Access in Recovery Mode

Your Mac’s Recovery Mode is a treasure trove of useful tools, and it’s the easiest way to wipe your computer and start from scratch. Shut down your Mac, turn it on while holding down Command+R. Your Mac will boot into the recovery partition.

If you’re using an older Mac (from 2010 or earlier), there’s a chance that you can’t use Recovery Mode. On those devices, hold “Option” while turning your computer on, then select the recovery partition instead.

If neither of these options work, don’t panic! You’ve got a couple of options yet. You can access recovery without a partition using Network Recovery: hold Command+Shift+R while turning on your Mac and it will download the Recovery features for you. Failing that, you can create a bootable USB installer for macOS Sierra, and boot from that by holding “Option” while turning on your Mac.

Once you’ve managed to open up the Recovery Mode in some fashion, we can move on to wiping your drive securely.

Step Two: Securely Wipe Your Hard Drive (Optional)

If you want to re-install your operating system, but leave your files in place, you can skip this step. Your user accounts and files will stay exactly where they are—only your operating system will be overwritten. We recommend backing up files before you do this, just in case, but otherwise you’re ready for step three.

Install

If you want a truly clean installation, however, you need to first wipe your hard drive. We’ve shown you how to securely wipe a hard drive with your Mac, and doing so in Recovery Mode isn’t really different from doing so within macOS.

To get started, click the Disk Utility option.

Depending on how you started Recovery Mode, you may be presented with the option to start Disk Utility right away, as seen above. If not you can find Disk Utility in the menu bar: click Utilities then Disk Utility.

You’ll now see your list of hard drives. Click your primary drive, then click “Erase”

If you’re wiping a mechanical drive, click “Security Options” in the window that pops up. (If your Mac has a solid state drive, you can skip this part: your SSD will already securely erase files thanks to TRIM. You still need to wipe the drive, however, or your files will remain in place, so skip to the end of this step to do so.)

Now move the dial up, to randomly write data over your entire drive. You only need to write over a drive once to securely wipe it, but if you’re paranoid you can also wipe it three or five times.

RELATED:How to Wipe Your Mac and Reinstall macOS from Scratch

Click “OK” once you’ve decided, but remember: if your Mac has a solid state drive, you do not need to use these options. Just give your drive a name (I recommend “Macintosh HD”, just for consistency’s sake), then click “Erase” to start the overwriting process.

If you opted to wipe your drive securely, this might take a while—30 minutes to an hour is not unreasonable for one pass. If you choose three or five passes, you might want to leave this running overnight.

Step Three: Reinstall macOS

With your information wipe complete, you are now ready to reinstall macOS. 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.

How To Copy Mac Os X Install Usb

You’ll be asked which hard drive you want to install to. Choose the Macintosh HD you named earlier.

Create Macos Install Usb El Capitan

Just like that, macOS will begin installing.

This might take a while. Eventually your Mac will restart and ask you to create an account. If you’re giving your Mac away, or selling it, I recommend that you simply shut down at this point and let whoever you’re giving your Mac to create their own account. After all, it’s theirs now. Otherwise, enjoy your now-fresh Mac!

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