Erase Hard Drive Mac Os X 10.6 8

Updated December 2, 2020: added information for new Macs with Apple processors.

All too often I’ve seen people buy a used Mac only to find that the seller did not properly erase the Mac first. Sellers sometimes just delete their documents, leaving poorly configured and obsolete apps lying around. Or worse yet a malicious security threat or connections to their old account. Here is how to properly erase a Macintosh, ensuring that:

The Secure Empty Trash command prompts Mac OS X to perform a seven-pass erasure of the file. Due to Mac OS X's need to rewrite file data on the hard disk multiple times. Answer: Apple’s Disk Utility securely erases data from hard drives, and it’s built right in to OS X. If you’re running OS X 10.7 or higher, you do this through Internet Recovery. Restart your Mac and hold down Command + R during the start up process. Don’t let up on those keys until the Apple logo appears.

  • If you are selling or recycling your Mac, none of your personal information remains
  • If you are buying a used Mac, none of the previous owner’s configuration will mess things up
  • When you normally delete your files in Mac OS X, the operating system is only forgetting where those particular files are placed, while the data still physically remains on the drive. Beginning with Mac OS 10.3, Apple enhanced its security by introducing the Secure Empty Trash feature, which follows the U.S. DoD pattern of overwriting data.
  • Insert a compatible Mac OS X install DVD, restart with the C key held down, use the Disk Utility to erase the internal drive, and install a fresh OS. (114345) More Less.

Take note of what system version you are running, as some of these instructions will vary depending on the version. You can find that in the Apple menu > About This Mac.

Back up any data

These steps will completely and irrecoverably erase everything on your Mac. If you have anything on this Mac that you want to keep you’ll want to back it up. Photos, contacts, documents, application installers, etc. Many of these things are saved to iCloud but not necessarily. When we are done the only thing left will be a squeaky clean computer as good as from the factory.

Update your software (optional)

If the computer is going to be reused or sold, you probably want to upgrade the software to the latest supported OS if it isn’t already. It’s better to do an upgrade and then erase rather than an erase and then upgrade. If you’re planning to simply recycle the computer it doesn’t matter so you can skip this.

You can view my reference chart to see what version of macOS you can run, and where to get each version.

Log out of your accounts

This isn’t strictly necessary but it will remove one of your five allowed iTunes authorizations and will remove the computer from your iCloud account. In particular, you’ll want to:

  • Deauthorize iTunes. Instructions are the same for the Music app in macOS Catalina. You only need to do it for Music or Apple TV, not both.
  • Log out of iCloud (in the Apple menu > System Preferences > iCloud), if prompted you can delete the local data, since you have all of this in iCloud already.
  • Log out of iMessage (open iMessage, click the iMessage menu, click the Accounts tab, click the iMessage account on the left column, and then click the button to sign out)
  • Log out of FaceTime (similar to logging out of iMessage).
  • Deactivate any third party software that has a limited number of authorizations. Most consumer-grade software doesn’t do this, but some expensive professional software does. Instructions for this will vary depending on the specific software.

Start up in macOS Recovery Mode

Be sure to remove all devices from your computer except for necessary items like the mouse and keyboard. You don’t want to accidentally erase an external hard drive.

For macOS 11 or higher with an Apple processor

  1. Turn your computer off
  2. Press and hold the power button until you see icons
  3. Click the Options icon then click Continue

For macOS 10.7 or higher with an Intel processor

  1. Turn your Mac off
  2. Press the power button to turn the Mac back on and immediately press and hold the Command + R keys on your keyboard
  3. When you see the Apple logo or globe you can release the keys
  4. Follow any prompts such as entering your WiFi password or choosing your language

Shortcut: If you are running macOS 10.13 High Sierra or later and you want to install the latest OS your computer supports rather than the currently installed OS, use Command + Option + R instead. You can release the keys when you see the globe, then choose your WiFi network when prompted.

For Mac OS X 10.6 and lower

You’ll need to boot using a Mac OS X disc. If you don’t have your disc you may need to upgrade the system software to a newer version first and then try again. Or you’ll need to enter Target Disk Mode and connect it to another Mac to erase with Disk Utility.

  1. With the computer powered on, insert your Mac OS X install disc or the recovery disc that came with your Mac
  2. Turn off your Mac
  3. Press the power button to turn the Mac back on and immediately press and hold the Option key on your keyboard
  4. Release the Option key when you see the boot selector
  5. Use your arrow keys on your keyboard or your mouse to select the install disc (it could take up to a minute to appear)
  6. click the arrow below the install disc or press Return on your keyboard to activate it

Erase your disk

For Macs with an Apple Processor

  1. Use the WiFi icon in the upper right corner of your screen to connect to WiFi if you are not already
  2. Click the “Utility” menu on the top of the screen and choose “Terminal”
  3. In the terminal window type resetpassword and then press return
  4. Click on the new window that pops up
  5. Click the Recovery Assistant menu
  6. Click “Erase Mac…” and follow the prompts to erase your Mac

For Macs with an Intel Processor

  1. Once in Recovery Mode, click the Disk Utility from the menu and then click “Continue”
  2. If running macOS 10.15 Catalina or 11 Big Sur you will see two similarly named drives on the left column, one with “Data” on the end. Click the Data drive to highlight it, then click the Minus Volume button above to remove the volume. Choose “Delete” (not Delete Volume Group). If you aren’t running Catalina or if you only see one internal drive skip this step.
  3. Click to highlight your hard drive name on the left column, Macintosh HD by default. If you are running macOS 10.12 or lower it will be indented slightly behind the model name of the hard drive.
  4. Click the Erase button. Depending on your OS version this will either be on the top button bar or on a tab to the right.
  5. If you want to destroy sensitive data, click the “Security Options” button and choose the level you want to run. Each pass takes about two hours depending on the speed of your drive. A single pass is good enough for most people. But consider more if you have any highly sensitive data. If you have an SSD or Fusion Drive you may not have this button because a standard erase is far more destructive.
  6. If the Format is listed as APFS, leave it as is. Otherwise make sure it says “MacOS Extended (Journaled)”.
  7. Click Erase and wait for it to complete. Erasing an SSD or an insecure erase takes just a few seconds. A secure hard drive erase can take hours. If it fails pretty much immediately just try again. Sometimes it takes a couple of tries. If it runs for a long time and then fails, you may have a bad hard drive.
  8. Click OK after it has finished.
  9. Close Disk Utility with the red dot button.
  10. Press Command-Q to shut down if you are just disposing of the computer, otherwise continue on to install the OS.

Install the OS (Optional)

If you are only recycling the computer and don’t need to prepare it for another user you can skip this step and shut down your computer by pressing Command-Q.

  1. Make sure you are connected to your WiFi network by clicking the WiFi icon in the upper right corner of your screen.
  2. Click the button to reinstall the OS and follow the prompts.
  3. After the OS is installed you can either go through the account creation process or, if you are selling the computer to someone else, press Command-Q to quit and shut down. The next time the Mac is turned on the new user will be greeted with the same welcome screen.

Requirements

  • Fast internet connection: this will download the OS from the internet. It usually takes 30 to 60 minutes on a cable or fiber connection, or it could take 6 to 12 hours on a DSL connection. The download is about 6 to 8 GB.
  • For macOS 10.11 or earlier, the currently installed OS must already be in your Mac App Store account. Check this in the Apple menu > App Store > Purchased. If the currently installed OS is not on your purchase list you must upgrade to at least macOS 10.12 and then do the full erase, or solicit the account of someone who does have the currently installed version in their account.
  • Compatible network connection: Most home and small business routers since about 2005 should have the appropriate configuration by default. If you are unsure click the WiFi icon in the top right corner of your screen while holding the “Option” key. In light grey lettering you will see your current security type. Or just try it and see if it works.
10.6

You must be on either:

  • wired ethernet connection,
  • WiFi connection without a password, or
  • WiFi connection with WPA-Personal or WPA2-Personal encryption.

You cannot install via:

  • captive WiFi connection (one where you get a popup on connecting such as at a coffee shop or library),
  • WiFi with WEP encryption
  • WiFi with WPA-Enterprise encryption
  • WiFi with certificate-based encryption, or
  • a connection that requires a proxy to be configured.

Further help

If you are an existing customer who needs help with this or if you have other questions, or if you are in San Francisco and interested in becoming a client I invite you to book an appointment with me. Otherwise, you may wish to contact Apple Support or to find a local Apple consultant.

Photo by Kim Gorga on Unsplash

Disk Utility within Mac OS X provides a range of disk management tools, from erasing and repartitioning hard disks to restoring images and repairing volumes. It's a simple way of interacting with attached storage on your Mac.

Beyond this graphical front-end are some powerful command-line tools that we can use directly. In this series, we'll look at how to replicate the functionality of Disk Utility at the command-line.

The following guide will require the use of an external hard drive which will be erased and partitioned.

Terminology

A partition is a logical storage unit located on a hard disk. A hard disk can contain a single partition, making use of all the space it contains, or it can be split into multiple partitions.

In order to store data on a partition, it needs a filesystem. Once a partition has been formatted, this combination of partition and filesystem is known as a volume.

Here's a USB hard drive that has been split into 16 partitions, all of which will display separately on the Mac as separate volumes since they've been formatted, though they are all on the same drive.

Imagine you have a loft apartment that's just four outer walls. Think of partitioning as putting up dividing walls to create additional rooms. The more walls you put up, the more rooms you'll have, but all limited to the total amount of space you first had available.

But these rooms can't be used yet, not until you decide what each room will be. Formatting a disk partition is no different than deciding which room will be the bedroom or kitchen. At that point, it becomes a volume.

With the introduction of OS X Lion, your Mac's hard disk is split into two partitions with two corresponding volumes. The first is hidden and named Recovery HD for OS X Recovery, allowing you to reinstall OS X without needing any physical media. The second is the more familiar Macintosh HD.

Benefits of the Command-Line

Disk Utility is more than adequate to perform any form of disk management for most users. It's also safer than the command-line, displaying warning dialogs before proceeding with any potentially destructive functions.

For more experienced users, the command-line offers a greater level of flexibility and control so that what would normally require several different interactions and mouse clicks can be done with just one command.

Disk Information with diskutil

The diskutil command provides many of the features of Disk Utility, from verifying and repairing volumes to changing partition information.

To view the full list of available options for the command, enter the command diskutil.

Partition Information

Using the list option will display some basic information about all available volumes and drives attached. Within Terminal, enter:

In the following screenshot, you can see both the Recovery HD and Macintosh HD, both partitions contained on the Mac's internal hard disk. An external hard disk is also connected with a volume labeled Untitled.

There are some hidden partitions (such as EFI) used for the purposes of providing drivers and settings during boot. These aren't volumes since they cannot be mounted.

Depending on whether you have features such as FileVault 2 or Fusion Drive, your partition layout might differ slightly to what is pictured above.

For many of the options within diskutil, it's necessary to use the disk or partition's Identifier. Using list will provide you with this information.

Should you have a number of disks and only want to view information about a specific one, you can append the disk identifier to the command:

The first number represents the physical disk identifier. The number following the letter 's' represents the partition number. If a disk has three partitions, it would follow this convention:

  • disk2s1
  • disk2s2
  • disk2s3

In addition to list, you can also use info with the corresponding identifier to display even further information, like so:

Verifying and Repairing Volumes

As within Disk Utility, the diskutil command can be used to verify or repair volumes of any errors and is very straightforward to do using either verifyVolume or repairVolume. These options don't need the disk identifier, just the volume's name:

If the feedback within Terminal looks familiar, that's because it's the same information Disk Utility provides.

Disk permissions can also be verified and repaired using two similar commands:

Erasing Disks

Erasing disks from the command-line can be a dangerous process as there aren't any warnings or confirmations. One typo could lead to irreversible data loss if there's no backup to restore from. If you're not familiar with the command-line, Disk Utility is just as capable.

You can either erase a whole disk which will remove any partitions stored upon it, or individual volumes without affecting others.

Erase Hard Drive Mac Os X 10.6 8

To erase an entire disk, you'll need the disk identifier, enter the following, adjusting the disk identifier to suit:

You'll notice this command has a little more going on than previous ones. The structure of the command is:

Erasing a whole disk will clear any partitions and create a new, single partition, before formatting it as a volume.

Filesystem

You can specify the filesystem to format the partition in by using any that are supported. The most common would be JHFS+ which is more commonly known as Mac OS Extended (Journaled).

To find out which filesystems you can use, enter:

diskutil listFilesystems

Name

This simply refers to the name of the volume that will be created. In this instance, I've just labelled the volume as 'Test'.

Disk Identifier

Only the primary part of the identifier (i.e. disk1, disk2, disk3...) is needed. The additional segment indicating the partition number is omitted.

Erasing Volumes

Erasing volumes doesn't erase or affect the entire disk, only the volume you specify.

Here is an external drive that's partitioned with two volumes, FirstVolume and SecondVolume. To erase SecondVolume, the command is:

The command's structure is almost identical to using eraseDisk, only that you specify the volume rather than disk. Should a disk contain multiple volumes, only the one you specify is altered.

Reformatting Volumes

Erase Hard Drive Mac Os X 10.6 80 6 8 Upgrade El Capitan

You'll notice that erasing a volume requires specifying the filesystem and name. This can be a bit tedious if you don't actually want to change either of these, but simply want to erase the contents.

Instead, the reformat option will erase the contents of the volume without requiring the filesystem or name, provided these are to remain unchanged.

Erase Hard Drive Mac Os X 10.6 840

Now, the volume will be erased but retain the existing filesystem and name.

Renaming Volumes

Erase Hard Drive Mac Os X 10.6 8 Update Mac Os X 10 6 8

Within the Finder, you can quite easily rename the volume by selecting it on your desktop and pressing the Return key, just like you would any file or folder.

Erase Hard Drive Mac Os X 10.6 8 Mac Os X 10 6 8 Free Download

Renaming volumes within the Terminal uses a different method than the renaming of files and folder, something accomplished by using the command:

Erase Hard Drive Mac Os X 10.6 8ate Mac Os X 10 6 8

Wrapping Up

We've only scratched the surface of diskutil yet covered quite a lot. While the graphical interface of Disk Utility can be easier to interact with, a task that would involve several steps can be accomplished with just one single command.

Erase Hard Drive Mac Os X 10.6 8.1

In the next part of this series, we'll cover how to manage partitioning and modify volumes.

Erase Hard Drive Mac Os X 10.6.8

You can purchase the complete guide to Disk Management From the Command-Line that includes Building an OS X Triage Drive as an ebook in ePub and PDF format for just $0.99.