How to Perform a Clean Install of OS X Mavericks

A clean install requires more steps than the upgrade install

What to Know

  • Insert USB installer, restart Mac and hold the Option key, open Disk Utility, erase the startup drive, and install Mavericks on this drive.
  • Before you begin, back up your Mac and create a bootable version of the OS X Mavericks installer on a USB drive.

 A clean install of OS X Mavericks allows you to start fresh, either by erasing all of the data on your startup drive and then installing OS X Mavericks or by installing Mavericks on a non-startup drive; that is, a drive that doesn't contain an operating system. Here's how to perform a clean install of OS X Mavericks; all you need is a USB flash drive.

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How to Perform a Clean Install of OS X Mavericks on a Mac's Startup Drive

How to Perform a Clean Install of OS X Mavericks on a Mac's Startup Drive
Screen shot courtesy of Coyote Moon, Inc.

The OS X Installer can perform both an upgrade install (the default) and a clean install on a non-startup drive. However, when it comes to performing a clean install of Mavericks on a startup drive, the process is a bit more difficult.

Unlike the older versions of OS X that were distributed on optical media, the downloaded versions of OS X don't provide a bootable installer. Instead, you run the installation app directly on your Mac under the older version of OS X.

This works fine for the upgrade install and the non-startup drive install, but it doesn't allow you to erase your startup drive, a necessary process if you want to perform a clean install.

What You Need for a Clean Install of OS X Mavericks

  • The OS X Mavericks Installer, available from the Mac App Store.
  • A Mac that meets the minimum requirements for OS X Mavericks.
  • A backup of your current startup drive. This can be a Time Machine backup or a clone of your startup drive.
  • A startup drive that contains OS X Snow Leopard or later, and that you're willing to erase.

Let's Get Started

  1. We're going to start the process by taking care of two preliminary tasks that must be performed.
  2. Since the clean install process will erase all of the data on your startup drive, we must have a current backup before we can begin. I recommend performing a Time Machine backup and creating a clone of your startup drive. My recommendation is based on two things, First, I'm paranoid about backups, and prefer to have multiple copies for safety. And second, you can use the Time Machine backup or clone as the source for migrating your user data back to your startup drive after OS X Mavericks is installed. Back Up Your Startup Disk Using Disk Utility (clone)
  3. The second step we need to perform to prepare for the clean install is to create a bootable version of the OS X Mavericks installer. You can do this by following these instructions: Create a Bootable Version of the OS X Mavericks Installer on a USB Flash Drive

Once you complete these two preliminary tasks, you're ready to begin the clean install process.

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Install OS X Mavericks From the Bootable USB Flash Drive

Install OS X Mavericks From the Bootable USB Flash Drive
Screen shot courtesy of Coyote Moon, Inc.

Now that you have a bootable USB flash drive containing the OS X Mavericks Installer (see page 1), and a current backup, you're ready to start the clean install of Mavericks on your Mac.

Boot From the OS X Mavericks Installer

1. Plug the USB flash drive that contains the Mavericks installer into one of the USB ports on your Mac. I don't recommend using an external USB hub for the installation. While it may work fine, sometimes you can run into an issue that will cause the install to fail. Why tempt fate? Use one of the USB ports on your Mac.​

2. Restart your Mac while holding down the option key​

3. The OS X startup manager will appear. Use your keyboard's arrow keys to select the USB flash drive, which, if you haven't changed the name, will be OS X Base System.​

4. Press the Enter key to start your Mac from the OS X Mavericks installer on the flash drive.​

5. After a short time, you'll see the installer's Welcome screen asking you to select a language. Make your selection and click the right-facing arrow button to continue.

Use Disk Utility to Erase the Startup Drive

1. The Install OS X Mavericks window will display, along with the usual menu bar across the top of your monitor.​

2. From the menu bar select Utilities, Disk Utility.​

3. Disk Utility will launch and display the drives available to your Mac.​

4. In the Disk Utility sidebar, select your Mac's startup drive, which is usually named Macintosh HD. ​​

You are about to erase your Mac's startup drive. Make sure you have a current backup before proceeding.

5. Click the Erase tab.​

6. Make sure the Format drop-down menu is set to Mac OS Extended (Journaled).​

7. Click the Erase button.​

8. You will be asked to confirm that you really, really want to erase your startup drive. (You do have a current backup, right?) Click the Erase button to proceed.​

9. Your startup drive will be wiped clean, enabling you to perform a clean install of OS X Mavericks.​

10. Once the drive is erased, you can quit Disk Utility by selecting Disk Utility, Quit Disk Utility from the menu bar.​

11. You'll be returned to the Mavericks installer.

Start the Mavericks Install Process

1. In the Install OS X Mavericks screen, click the Continue button.​

2. The Mavericks licensing terms will display. Read through the terms, and then click Agree.​

3. The installer will display a list of drives attached to your Mac that you can install Mavericks on. Select the startup drive you erased in the previous step, and then click Install.​

4. The Mavericks installer will start the installation process, copying the new OS to your startup drive. The process can take a bit of time, anywhere from 15 minutes to an hour or more, depending on your Mac and how it's configured. So relax, grab a coffee, or go for a walk. The Mavericks installer will continue to work at its own pace. When it's ready, it will automatically restart your Mac.​

5. Once your Mac restarts, proceed to the next page to complete the OS X Mavericks initial configuration process.

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Configure OS X Mavericks Initial Settings

Configure OS X Mavericks Initial Settings
Screen shot courtesy of Coyote Moon, Inc.

Once the OS X Mavericks installer automatically restarts your Mac, the bulk of the installation process is complete. There are some housekeeping chores to be performed by the installer, such as removing temp files and clearing out a cache file or two, but eventually you'll be greeted by Mavericks' first-startup Welcome display.

Initial OS X Mavericks Setup

Because you're performing a clean install of OS X Mavericks, you'll need to run through the first-startup setup routine that configures some of the basic preferences needed by the OS, as well as create an administrator account to use with Mavericks.

  1. In the Welcome screen, select the country where you will be using the Mac, and then click Continue.​
  2. Select the type of keyboard layout you're using, and then click Continue.​
  3. The Migration Assistant window will display, letting you choose how you wish to transfer information from your backup to the new clean install of OS X Mavericks. The choices are:
    1. From a Mac, Time Machine backup, or startup disk
    2. From a Windows PC
    3. Don't transfer any information
  4. If you backed up your data before you performed the clean install, you can select the first option to restore your user data and apps from a Time Machine backup, or from a clone of your old startup drive. You can also choose not to transfer your user data and just continue with the installation. Remember, you can always use the Migration Assistant at a later date to restore your old information.​
  5. Make your selection, and click Continue. This guide assumes you chose not to restore data at this time, and that you'll do it at a later date using the Migration Assistant. If you did choose to restore your user data, then follow the onscreen instructions to complete the process.​
  6. The Apple ID screen will display, allowing you to sign in with your Apple ID and password. You'll need to supply your Apple ID to access iTunes, the Mac App Store, and any iCloud services. You can also elect not to supply the information at this time. Click Continue when ready.​
  7. The Terms and Conditions will once again display; click Agree to continue.​
  8. A drop-down sheet will ask if you really and truly agree; click the Agree button.​
  9. The Create a Computer Account screen will display. This is where you will create an administrator account for use with OS X Mavericks. If you plan to use the Migration Assistant to move your old user data over, then I recommend giving the administrator account you create now a different name than the administrator account you'll move from your backup. This will ensure that there won't be any conflict between the new account and the old one.​
  10. Enter your full name, as well as an account name. The account name is also called the short name. The account name is used as the name of your home folder as well. Although not a requirement, I like to use a single name with no spaces or punctuation for the account name.​
  11. Enter a password to use for this account. Verify the password by entering it again.​
  12. Place a check mark in the "Require password to unlock screen" box. This will require you to enter your password after your screen or Mac awakens from sleep.​
  13. Place a check mark in the "Allow my Apple ID to reset this password" box. This allows you to reset the account password if you should forget it.​
  14. Set the Time Zone based on your current location to allow it to automatically track your location information.​
  15. Send Diagnostics & Usage Data to Apple. This option allows your Mac to send log files to Apple from time to time. The information sent is not tied back to the user and remains anonymous, or so I am told.​
  16. Fill in the form and press Continue.​
  17. The Registration screen will display, allowing you to register your Mac with its new install of Mavericks with Apple. You can also choose not to register. Make your selection and click Continue.​
  18. Your Mac will finish the setup process. After a short delay, it will display the Mavericks Desktop, signifying that your Mac is ready for you to explore your new version of OS X.

Have fun!

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