What keys do you press to erase a Mac?

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Quick Answer

To erase and reset a Mac to factory settings, you need to reboot into Recovery Mode and use the Disk Utility program. The basic steps are:

Restart your Mac and hold down Command+R immediately after hearing the startup chime to boot into Recovery Mode.
Select Disk Utility from the Utilities window.

Click the internal hard drive in the sidebar.
Click the Erase button.
Choose a format like Mac OS Extended (Journaled).

Click Erase again to confirm.
Quit Disk Utility when done and choose to Reinstall macOS to do a clean install.

This will completely wipe the hard drive and restore the Mac to out-of-the-box state. All data will be erased so make sure to backup first.

What Exactly Does Erasing a Mac Do?

When you erase a Mac, you are wiping the entire internal hard drive clean and resetting it to a factory-fresh state. This erases all user data, applications, settings, accounts, and any files stored on the drive.

Essentially, erasing a Mac does the following:

Removes all user accounts and related preferences.

Deletes all applications and third-party software.
Resets system settings and preferences.
Wipes all files, documents, photos, music, videos, downloads folder contents.

Erases all cached and temporary system files.
Reformats the hard drive.

After erasing, the Mac will be in the same clean condition as if you just took it out of the box for the first time. This can be useful if you want to wipe a Mac before selling or giving it away to someone else. It’s also commonly done if your Mac is having performance issues or problems that are difficult to troubleshoot, erasing will give you a fresh start.

When Would You Want to Erase a Mac?

Here are some of the most common reasons to completely erase a Mac:

Selling or gifting your Mac – Wiping it protects your personal data from falling into the wrong hands.
Eliminating malware or viruses – If your Mac is infected, erasing it can ensure the malware is completely removed.

Fixing performance problems – Erasing can help improve slow performance, crashes, or other glitches.
Resolving buggy behavior – If you’re having system issues that are hard to pinpoint, a clean slate can help.
Removing sensitive data – Before disposing of or recycling a Mac, you’ll want to wipe sensitive files beyond recovery.

Installing major operating system updates – New macOS versions sometimes run better on a blank drive.
Returning a leased Mac – Leased or borrowed Macs should be erased before being returned.

The key is that wiping your Mac gives you a completely fresh start by erasing everything on the drive and resetting it to factory conditions.

How to Erase and Reset a Mac

Here is the step-by-step process for completely erasing and resetting a Mac to factory settings:

1. Backup Your Mac Before Erasing

Before wiping your Mac, it’s critical to backup all important files you want to keep. Here are some backup options:

Copy important files to an external hard drive or cloud storage.

Use Time Machine to backup your entire hard drive to an external drive.
Use cloud backup services like iCloud or Carbonite to backup your files online.

Double check that your files are safely backed up to another location before proceeding. Once you erase, they cannot be recovered.

2. Restart Your Mac into Recovery Mode

To erase your Mac, you need to boot into a special Recovery Mode which loads recovery tools from a hidden partition:

Fully shut down your Mac
Restart your Mac and immediately hold down Command (⌘) + R

Hold the keys until you see the Recovery Mode screen appear

This will boot your Mac from the recovery partition and display the macOS Utilities window.

3. Launch Disk Utility from the Utilities Menu

In the macOS Utilities window:

Select Disk Utility from the options.
Click Continue to open Disk Utility.

Disk Utility is the program we will use to erase your hard drive.

4. Select Your Internal Hard Drive

In Disk Utility you will see a list of available drives on the left.

Select your main internal hard drive volume from the sidebar.
Usually named Macintosh HD.

This is the drive you want to erase. Double check you have the correct one selected.

5. Click Erase in the Top Menu

With your internal hard drive volume highlighted:

Click the Erase button in the toolbar.

This will display the Erase popup window.

Here you can configure the erasing options.

6. Choose a Format and Scheme

It’s best to use a common Mac format:

Choose Mac OS Extended (Journaled) as the format.
Use GUID Partition Map for the scheme.

This will format the drive in the standard Mac file system to make it bootable.

7. Type a Name and Click Erase

Give your erased volume a name, like “Macintosh HD” then proceed:

Type a name into the Name field.
Click the Erase button to proceed.

A pop-up will warn that all data will be erased. Confirm by clicking Erase again.

8. Wait for Disk Erase to Complete

It will take several minutes for the drive to be fully erased:

A progress bar will track the erase progress.

The disk will be unmounted when finished.
Once completed, click Done to close Disk Utility.

Your Mac’s hard drive is now fully wiped and reset to factory defaults.

9. Reinstall macOS (Optional)

With your drive erased, you can now choose to reinstall a fresh copy of macOS:

Quit Disk Utility and return to the macOS Utilities window.
Select Reinstall macOS from the options.

Follow the prompts to install a new OS system.

Your Mac will be like new again! Be sure to restore your data from backups.

Alternative Method Using Terminal

An alternative to using Disk Utility is to erase your Mac from the Terminal command line. Here are the steps:

Boot to Recovery Mode as explained above.
Launch Terminal from the Utilities menu.
Type diskutil list and find your internal drive.

Run diskutil eraseDisk JHFS+ "Macintosh HD" diskX (replace X with your disk)
Type Y to confirm the erase and wait for completion.
You can now reinstall macOS if desired.

This will accomplish the same full system erase as Disk Utility, just using command line tools.

What Gets Saved When You Erase a Mac?

When erasing a Mac, all files, apps, accounts, and personal data will be wiped from the drive. However, there are a few things that do not get erased:

The macOS system software – The erase leaves the base OS intact for reinstallation.

Firmware settings – Settings stored in firmware like boot mode and device IDs are not touched.
Recovery partition – This hidden system partition for utilities is still available.
Find My Mac activation – The Mac’s activation lock stays enabled until you sign out of Find My Mac.

So core system resources needed for operation remain while everything else is securely wiped.

Tips for Erasing a Mac

Follow these tips for a smooth erase process:

Use a wired internet connection for recovery mode to avoid WiFi issues.

Know your Apple ID credentials to deactivate Find My Mac activation lock.
Make sure you have drive space available equal to your data size for Time Machine backups.
Allow several hours for a full drive erase, especially on large drives.

Have the original macOS installer handy in case you need to reinstall the OS.

Can You Recover Data After Erasing a Mac?

Once a Mac drive has been completely erased, it is near impossible to recover the old data using consumer tools. However, forensics experts may be able to recover remnants of old files by directly examining the drive platters at a very low level. So while an erase offers strong protection against everyday data recovery attempts, it does not guarantee absolute deletion in all cases. The best way to ensure confidential data is not recoverable is to physically destroy the drive.

Downsides to Erasing Your Mac

While wiping your Mac can fix many issues and refresh the computer, there are a few downsides to consider:

It can take many hours to fully backup, erase, and restore data.
You may lose some preferences, settings, caches, etc. that cannot be backed up.
If your apps were not downloaded from the App Store, you’ll have to reinstall each one.

You’ll have to reset up accounts,preferences, and settings after erasing.
It interrupts your normal use of the Mac for a period of time.

For these reasons, you may want to try less drastic troubleshooting first unless the issues are very serious.

Frequently Asked Questions

Is erasing the same as formatting a hard drive?

Yes, the erase process fully formats and repartitions the drive. All file system structures are deleted.

Can files be recovered after erasing a Mac hard drive?

It’s very difficult for average users to recover erased files. However, advanced forensics experts may be able to recover some data by examining the drive directly.

Does erasing improve Mac performance and speed?

Often yes, because it clears out clutter, bogged down systems files, caches and more. The boost may only be temporary however.

Does an erase remove pre-installed apps like GarageBand?

Yes, all apps including pre-installed ones are wiped from the drive during an erase.

Should I backup an erased Mac from Time Machine?

No, you should not restore from a Time Machine backup after erasing.Doing a clean macOS install is recommended.

Is there a quick way to erase a Mac without reinstalling macOS?

No, the system files are erased too. You’ll need to reinstall macOS for it to be bootable again.

What if I don’t have the original macOS installer after erasing?

You can download the macOS installer again from the App Store by booting to Recovery Mode if needed.

Is it OK to erase SSDs or flash storage the same way as hard drives?

Yes, the process is the same for erasing and reformatting SSDs or flash storage like USB sticks.

Conclusion

Erasing and resetting a Mac clears out all old data and gives you a fresh start. While the process takes some time and effort, it can resolve many issues, improve performance, and prepare your computer for sale or disposal. Just be absolutely sure to have backups of anything important on your Mac before proceeding with an erase. With the right precautions, wiping your Mac with Disk Utility or Terminal can be an easy process.