How do you wipe a Mac hard drive?

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How do you wipe a Mac hard drive

Wiping a Mac hard drive completely erases all of the data on the drive and resets it to a clean state. This is useful when you want to sell, donate or recycle your Mac, as it removes all of your personal files and settings. A wiped drive can also help improve performance if the old data was causing crashes or slowdowns. Here are the main ways to wipe a Mac hard drive.

Why Would You Want to Wipe a Mac Hard Drive?

There are a few key reasons why you might want to wipe your Mac’s hard drive:

  • You’re selling or donating your Mac – Wiping the drive erases all personal data like documents, photos and emails.
  • You’re passing your Mac onto a family member or friend – A wiped drive gives them a fresh start.
  • You’re experiencing performance issues – Wiping the drive resets the Mac and can fix crashes or slowdowns.
  • You want to reinstall macOS with a clean slate – Wiping lets you start over from scratch.
  • You’re recycling or disposing of your Mac – A wiped drive keeps your personal data safe.

The main goal of wiping a drive is to ensure none of your personal data can still be accessed. For maximum security, the drive needs to be completely overwritten with new data.

How to Erase and Wipe a Mac Hard Drive

There are a couple ways to wipe a Mac hard drive, depending on your specific needs:

1. Use Disk Utility

Disk Utility is an app included with all Macs that can erase a hard drive. Here is how to use it:

  1. Open Disk Utility (located in Applications > Utilities)
  2. Select your startup disk in the sidebar
  3. Click “Erase” at the top of the window
  4. Choose a format – Mac OS Extended (Journaled) is recommended
  5. Select “Scheme – GUID Partition Map”
  6. Choose “Quick Erase” or “Secure Erase” depending on your needs (more details below)
  7. Click Erase

This will completely wipe the selected drive. Quick Erase is faster, while Secure Erase takes longer but ensures all data is completely overwritten.

2. Reinstall macOS

You can also wipe a hard drive by reinstalling macOS. Here’s how:

  1. Boot your Mac into Recovery Mode by holding Command + R on startup
  2. Select “Disk Utility” then click your startup disk
  3. Click “Erase” and confirm the settings
  4. Quit Disk Utility, then choose Reinstall macOS
  5. Follow the installer prompts to reinstall macOS with a wiped drive

This completely erases the disk before installing a brand new macOS system.

3. Use a Third-Party App

There are also third-party disk utility apps that can securely erase a hard drive:

  • CleanMyMac X – Has a “Smart Cleanup” option to securely erase free disk space.
  • Eraser – Open source app that can completely wipe drives.
  • Permanent Eraser – Wipes data so it can’t be recovered.

These apps offer advanced options like military-grade wiping algorithms to thoroughly scrub a hard drive clean.

Quick Erase vs. Secure Erase

Disk Utility lets you choose between a Quick Erase and Secure Erase when wiping a drive:

Quick Erase Secure Erase
Much faster, usually takes seconds Can take hours depending on drive size
Overwrites part of the drive once Overwrites entire drive 2-3 times with random data
Offers basic level of security Meets government security standards to fully prevent recovery

For maximum security, Secure Erase is recommended when wiping your Mac. But Quick Erase is fine if you just need to erase the drive quickly before donating or selling it.

How to Securely Erase Free Space on a Mac

In addition to completely wiping the entire hard drive, you can also just securely erase the free space on the drive if needed. Here’s how:

  1. Open Disk Utility
  2. Select your startup disk
  3. Click “Erase” then choose “Mac OS Extended (Journaled)” format
  4. Select “Scheme – GUID Partition Map”
  5. Choose “Quick Erase”
  6. Click “Erase”

This just erases any leftover free space on the drive. It’s much quicker than wiping the entire drive. All your personal files and macOS stay intact.

Using Third-Party Apps to Wipe Free Space

Apps like CleanMyMac X also offer secure erase features specifically for wiping unused disk space. The steps involve:

  1. Open the app and scan the drive.
  2. Select the “Secure Cleanup” option.
  3. Choose which unused space and inactive files to wipe.
  4. Run the data shredder to overwrite the selected free space.

Wiping just the unused space is a great way to add an extra level of security without having to erase your entire drive.

How to Securely Wipe a Mac SSD

Solid state drives (SSDs) are becoming more common in Macs. Unlike traditional hard disk drives, SSDs have no moving parts and store data differently. Here are some tips for wiping an SSD on a Mac:

  • Use Disk Utility as normal, but choose “Secure Erase” – Quick Erase is not secure enough for SSDs.
  • Consider using a third-party SSD eraser app for enhanced security.
  • Wipe unused space on the SSD occasionally for better performance.
  • Physically destroy the SSD if disposing of it – drills, hammers and sanders can damage chips.

Because SSDs spread data across memory chips, erasing an SSD multiple times is recommended. Destroying the physical chips is the only way to completely eliminate recoverable data.

How to Wipe a MacBook Hard Drive

To wipe the hard drive on a MacBook or MacBook Pro, the exact same methods apply:

  • Use Disk Utility in macOS, selecting the internal drive.
  • Erase the drive with Quick Erase or Secure Erase.
  • Reinstall macOS to wipe the drive before reinstallation.
  • Use a third-party disk utility app to securely overwrite data.

For MacBooks with SSDs, use Secure Erase and run it multiple times for the best wiping results.

How to Erase and Wipe an External Hard Drive

External hard drives link to your Mac via USB, Thunderbolt or FireWire. To wipe an external drive:

  1. Connect the drive to your Mac.
  2. Open Disk Utility and select the external drive.
  3. Click Erase and confirm the settings.
  4. Choose Quick or Secure Erase as needed.

This will fully erase the external drive, removing all files so no data can be recovered from it.

Using Terminal to Wipe an External Drive

You can also use Terminal to type a command to securely erase external drives. Here’s the basic process:

  1. Connect the external drive and get its disk identifier code (usually disk2 or higher).
  2. Open Terminal and run: diskutil list to get the disk ID.
  3. Type diskutil secureErase freespace VALUE /Volumes/NAME using the ID and drive name.
  4. Run a Secure Erase: diskutil secureErase LEVEL /Volumes/NAME using the ID.

This advanced method uses Terminal to target external drives connected to your Mac.

Important Tips When Wiping a Mac Hard Drive

Follow these additional tips when wiping your Mac:

  • Back up important data – Copy any important files and photos before wiping the drive.
  • Sign out of accounts – Make sure you are signed out of iCloud, iTunes, email services and any other accounts.
  • Deauthorize apps – Go to Preferences > Authorizations and deauthorize any authorized applications.
  • Disconnect external devices – Disconnect any external hard drives and peripherals before wiping.
  • Reset NVRAM and SMC – Reset these firmware settings after wiping the drive.

Alternative Ways to Sell or Donate a Used Mac

If you don’t want to wipe your Mac before selling or donating it, there are a couple options:

  • Log out of accounts – Make sure you log out of all accounts and services first.
  • Erase personalized files – Manually delete any documents, photos, emails and other personal files.
  • Reinstall macOS – You can reinstall macOS without erasing, keeping data intact.
  • Encrypt personal data – Use FileVault encryption before donation or sale.

While not as secure as wiping the hard drive, this prevents access to most personal data.

Recover Deleted Files After Wiping a Mac Hard Drive

If you wiped your Mac’s hard drive before remembering to backup important files, you may be able to recover deleted data:

  • Use data recovery software like EaseUS Data Recovery Wizard to scan for lost files after wiping the drive.
  • Recover files from a Time Machine backup, if you have one available.
  • Take your Mac to a data recovery service – costs start around $300.
  • On new M1 Macs, use the Duplicate System feature before wiping to make backups.

However, recovering wiped data is difficult and not always possible. That’s why it’s so important to properly backup your files first.

Reset NVRAM on a Wiped Mac

Resetting the NVRAM returns Mac firmware settings to default and can help fix issues after wiping your Mac. Here is how to reset the NVRAM:

  1. Shut down your Mac. The drive needs to be wiped already.
  2. Turn it back on and immediately press Command + Option + P + R.
  3. Hold the keys until you see the Apple logo appear and hear the startup sound again.
  4. Let go and allow boot to continue as normal.

The NVRAM reset clears any old settings to help stabilize performance after wiping the hard drive clean.

Reset SMC on a Wiped Mac

The System Management Controller (SMC) controls hardware functions. Resetting it can help if issues persist after wiping a Mac. To reset the SMC:

  1. Shut down Mac and unplug power cable.
  2. Press and hold the power button for 10 seconds.
  3. Release the button and plug the power cable back in.
  4. Wait a few seconds then turn your Mac back on.

This resets the SMC hardware controller to factory default, which often resolves any problems after wiping and erasing a Mac hard drive.

Conclusion

Wiping your Mac hard drive before selling, donating or disposing of it is important to keep personal data secure. The best options are to use Disk Utility to erase the drive, or reinstall macOS for a completely fresh system.

Make sure to back up important files first. And on Macs with SSDs, using a Secure Erase is recommended to fully prevent any file recovery. After wiping the hard drive, resetting NVRAM and SMC can help fix lingering issues.

With a little care, you can wipe a Mac hard drive quickly and easily. Just be sure to backup anything important, as recovering wiped data is extremely difficult.