Formatting / Partitioning / (Securely) Erasing A Hard Disk Or Volume
Article ID = 37Article Title = Formatting / Partitioning / (Securely) Erasing A Hard Disk Or Volume
Article Author(s) = Graham Needham (BH)
Article Created On = 13th July 2011
Article Last Updated = 20th October 2017
Article URL = https://www.macstrategy.com/article.php?37
Article Brief Description:
Instructions for Formatting / Partitioning / (Securely) Erasing A Hard Disk Or Volume
Formatting / Partitioning / (Securely) Erasing A Hard Disk Or Volume
NOTE: These processes can be used for multiple types of storage hardware including hard disks, Sold State Drives (SSDs), SD cards or USB sticks/flash drives.NOTE: This process will erase your selected volume / storage device and wipe all data from it.
NOTE: Remember to de-authorise/deactivate any software/services on the drive if it was used as a system disk.
Authorised/Activated Software and/or Services
- Apple software and related services
- Adobe Creative Suite/Creative Cloud and other products/services
- Microsoft Office 2011/2016/2019/365 for Mac but not Office 2004 or 2008
- Microsoft Windows and other products/services
- QuarkXPress
- Enfocus Pitstop Pro
- Mathworks MATLAB and Simulink Student Version
- Unity Technologies Unity 3D
- OnOne Software Perfect Photo Suite and other products
Follow these instructions:
- If you are not booting from a Mac OS X installation disc or external installation device, to be safe:
- Restart your computer.
- Quit all running applications.
- Disconnect all external devices except for monitor, keyboard, mouse and required storage volumes.
- Eject all optical discs.
- Unmount all servers.
- If you are not formatting an internal hard disk or SSD, connect or insert your storage device now.
- Go to Macintosh HD > Applications > Utilities > Disk Utility.
NOTE: USB boot drives or USB external installation devices only work on Intel Macs.
NOTE: A "volume" is a single partition. A "device" is the whole storage device that may contain one or more partitions (volumes). Individual volumes can have different names and usually mount on the desktop with their own icon (if this is turned on in Finder > Preferences > General > "Hard Disks" and "External Disks" ticked)
NOTE: Special information on using drives that are larger than 2TB.
NOTE: Special information on using Advanced Format Technology (AFT) drives.
- To Erase A Volume or Device with One Partition
- To Securely Erase A Volume or Device with One Partition
- To "Format" A Device
- To Partition A Device
To Erase A Volume or Device with One Partition
NOTE: This process will erase your selected volume / storage device and wipe all data from it.NOTE: Remember to de-authorise/deactivate any software/services on the drive if it was used as a system disk.
- On the left select the volume or device (with one partition) that you want to erase NOTE: with OS X 10.11 or later you can only erase a volume.
- On the right click on the "Erase" tab.
- Select the format, usually:
- "Mac OS Extended (Journaled)" for Mac OS X 10.3 to Mac OS X 10.6
- "OS X Extended (Journaled)" for OS X 10.7 to OS X 10.11
- "Mac OS Extended (Journaled)" for macOS 10.12
- "APFS" for macOS 10.13 or later - see article about APFS
- Enter the "Name" for your volume (if it's your main boot disk it's usually "Macintosh HD").
- If you have a PowerPC Mac running Mac OS X 10.4 or earlier that is capable of booting Mac OS 9 and you still want to be able to boot into Mac OS 9 tick the "Install Mac OS 9 Drivers" option.
- Click "Erase…".
NOTE: with macOS 10.13 or later Disk Utility only shows volumes by default and the Sidebar can be hidden - go to View menu > Show Sidebar and View menu > Show All Devices to see everything.
To Securely Erase A Volume or Device with One Partition
NOTE: This process will erase your selected volume / storage device and wipe all data from it.NOTE: Remember to de-authorise/deactivate any software/services on the drive if it was used as a system disk.
NOTE: We do not currently recommend securely erasing an SSD!
- On the left select the volume or device (with one partition) that you want to erase NOTE: with OS X 10.11 or later you can only erase a volume.
- On the right click on the "Erase" tab.
- Select the format, usually:
- "Mac OS Extended (Journaled)" for Mac OS X 10.3 to Mac OS X 10.6
- "OS X Extended (Journaled)" for OS X 10.7 to OS X 10.11
- "Mac OS Extended (Journaled)" for macOS 10.12
- "APFS" for macOS 10.13 or later - see article about APFS
- Enter the "Name" for your volume (if it's your main boot disk it's usually "Macintosh HD").
- If you're erasing a device and have a PowerPC Mac running Mac OS X 10.4 or earlier that is capable of booting Mac OS 9 and you still want to be able to boot into Mac OS 9 tick the "Install Mac OS 9 Drivers" option.
- Click the "Security Options…" button. Disk Utility - Secure Erase Options With OS X 10.9 And Earlier Disk Utility - Secure Erase Options With OS X 10.10 And Later
- Choose your desired level of security for the erase. NOTE: Some of the security levels are only available with certain versions of Mac OS X e.g. Mac OS X 10.4 or later. OS X 10.10 and later offers:
- Fastest = quick format
- > 2 pass (random data + zeroes)
- > DOE-compliant 3 pass (2 passes of random data + single pass of known data)
- Most secure = US DOD5220-22 M (writes over the data 7 times)
- Click OK and then "Erase…".
NOTE: with macOS 10.13 or later Disk Utility only shows volumes by default and the Sidebar can be hidden - go to View menu > Show Sidebar and View menu > Show All Devices to see everything.
To "Format" A Device
NOTE: This process will erase your selected volume / storage device and wipe all data from it.NOTE: Remember to de-authorise/deactivate any software/services on the drive if it was used as a system disk.
- On the left select the device that you want to format. NOTE: with macOS 10.13 or later Disk Utility only shows volumes by default and the Sidebar can be hidden - go to View menu > Show Sidebar and View menu > Show All Devices to see everything.
- On the right click on the "Partition" tab.
- Select "1 Partition" from the 'Volume Scheme' pop-up menu - in OS X 10.11 or later you can set the number of partitions you want using the + and - buttons (use the - button to change it to 1 partition).
- Enter the "Name" for your volume (if it's your main boot disk it's usually "Macintosh HD").
- Select the format, usually:
- "Mac OS Extended (Journaled)" for Mac OS X 10.3 to Mac OS X 10.6
- "OS X Extended (Journaled)" for OS X 10.7 to OS X 10.11
- "Mac OS Extended (Journaled)" for macOS 10.12
- "APFS" for macOS 10.13 or later - see article about APFS
- If you have a PowerPC Mac running Mac OS X 10.4 or earlier that is capable of booting Mac OS 9 and you still want to be able to boot into Mac OS 9 tick the "Install Mac OS 9 Drivers" option.
- Click "Apply".
To Partition A Device
NOTE: This process will erase your selected volume / storage device and wipe all data from it.NOTE: Remember to de-authorise/deactivate any software/services on the drive if it was used as a system disk.
- On the left select the device that you want to partition. NOTE: with macOS 10.13 or later Disk Utility only shows volumes by default and the Sidebar can be hidden - go to View menu > Show Sidebar and View menu > Show All Devices to see everything.
- On the right click on the "Partition" tab.
- Select your desired number of partitions (volumes) from the 'Volume Scheme' pop-up menu - in OS X 10.11 or later you can set the number of partitions you want using the + and - buttons. NOTE: Each volume can be of different size and format (by default Disk Utility will size partitions equally from the available storage capacity - you can either resize by dragging the partition shape/slider on the circle or by entering the required amount for "Size"). Disk Utility - Partition A Device With OS X 10.10 Or Earlier Disk Utility - Partition A Device With OS X 10.11 Or Later
- Enter the "Name" for each partition or volume (if it's your main boot partition it's usually named "Macintosh HD").
- Select the format, usually:
- "Mac OS Extended (Journaled)" for Mac OS X 10.3 to Mac OS X 10.6
- "OS X Extended (Journaled)" for OS X 10.7 to OS X 10.11
- "Mac OS Extended (Journaled)" for macOS 10.12
- "APFS" for macOS 10.13 or later - see article about APFS
- If you have a PowerPC Mac running Mac OS X 10.4 or earlier that is capable of booting Mac OS 9 and you still want to be able to boot into Mac OS 9 tick the "Install Mac OS 9 Drivers" option.
- Click the "Options…" button.
- Choose your desired partition scheme for this device NOTE: Partition schemes are only available with Disk Utility on later versions of Mac OS X e.g. Mac OS X 10.4 or later.
- GUID Partition Table = To be able to boot an Intel Mac
- Apple Partition Map = To be able to boot an PowerPC Mac or Intel Mac
- Master Boot Record = To be able to boot a DOS or Windows computer NOTE: If you are going to use the storage device:
- not as a boot disk select "Apple Partition Map".
- not as a boot disk but only on Mac OS X 10.4 or later select "GUID Partition Table".
- as a boot disk but only on Mac OS X 10.3 or earlier select "Apple Partition Map".
- as a boot disk on a PowerPC (G3, G4, G5) Mac select "Apple Partition Map".
- as a boot disk but only on an Intel Mac select "GUID Partition Table".
- as a boot disk but for both PowerPC and Intel Macs select "Apple Partition Map" e.g for an Emergency Boot Disk.
- as a boot disk but only for Windows select "Master Boot Record".
- as a boot disk and it is an SD Card or USB stick/flash drive select "GUID Partition Table".
- Click OK and then "Apply".
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