How to Completely Erase Your Mac and Start Fresh

What deleting everything on a Mac actually means

Deleting everything on your Mac means erasing the entire hard drive or solid-state drive (SSD) and reinstalling macOS from scratch. This is different from emptying the Trash or deleting individual files — you are removing the operating system itself, all your programs, and every file you have stored. When you do this, your Mac returns to the state it was in when it first left the factory.

Most people do this for one of three reasons: they are selling or giving away the Mac and want to remove their personal data, they are troubleshooting a serious software problem that a restart or update will not fix, or they want to reclaim storage space and start with a clean system. The process is straightforward but takes time and requires you to have a way to reinstall macOS afterward.

Key Takeaways

You must back up any files you want to keep before you erase, because erasing removes everything permanently and recovery is difficult.
The safest method is to use macOS Recovery (built into every Mac) to erase the drive and reinstall the operating system in one process.
If you are selling the Mac, use Erase All Content and Settings on newer Macs (2022 and later with Apple silicon) or Erase and Reinstall on older models to remove your data completely.
The entire process takes 30 minutes to several hours depending on your Mac model, internet speed, and how much data is on the drive.
You will need your Apple ID password and, on some Macs, your firmware password if you set one up previously.

Back up your files before you erase anything

Before you erase your Mac, you must copy any files you want to keep to an external drive, cloud storage, or another computer. Once you erase the drive, those files are gone. Recovery software exists, but it is expensive, unreliable, and should not be your plan.

The fastest way to back up is to use Time Machine, which is built into macOS. Plug in an external hard drive, open System Settings, go to General > Time Machine, and click "Add Backup Disk". Select your external drive and let Time Machine run. This creates a complete copy of your Mac that you can restore from later if you change your mind.

If you do not have an external drive, you can copy files manually to cloud storage like iCloud Drive, Google Drive, or Dropbox. Open Finder, select the files or folders you want to keep, and drag them to the cloud storage folder. This takes longer than Time Machine but works if you only have a few important files.

Erase your Mac using macOS Recovery

The built-in Recovery mode is the safest way to erase your Mac because it erases the drive and reinstalls macOS in one step, leaving no orphaned files behind. To start Recovery, shut down your Mac completely, then turn it on and when ready hold Command + R (or Command + Option + R for internet recovery, which downloads macOS from Apple's servers).

Your Mac will boot into Recovery mode, which shows the macOS Utilities window. Click "Disk Utility", then select your main drive (usually called "Macintosh HD" or your Mac's name) from the left sidebar. Click the Erase button at the top, choose a name for the drive (you can keep the default), set the format to APFS (the standard for modern Macs), and click Erase. This takes a few minutes.

After the drive is erased, close Disk Utility and you will return to macOS Utilities. Click "Reinstall macOS" and follow the prompts. Your Mac will read and install the operating system that originally came with your computer. This step takes 20 minutes to an hour depending on your internet speed. When it finishes, your Mac will restart and show the setup screen, as if it were brand new.

Using Erase All Content and Settings on newer Macs

If your Mac has Apple silicon (M1, M2, M3, or newer chip) and runs macOS Ventura or later, you can use Erase All Content and Settings instead of Recovery mode. This method is faster and simpler because it does not require you to restart into Recovery.

Open System Settings, go to General, scroll to the bottom, and click "Transfer or Reset". Click "Erase All Content and Settings". Your Mac will ask for your Apple ID password and will warn you that this action cannot be undone. Enter your password and click Continue. Your Mac will erase the drive and reinstall macOS automatically, then restart and show the setup screen.

This method is especially useful if you are selling your Mac, because it ensures that your Apple ID is removed from the device and a new owner cannot access your iCloud account, photos, or other personal data. The entire process takes 15 to 30 minutes.

What to do if you forgot your password or Apple ID

If you cannot remember your Apple ID password, you can reset it before you erase. Go to iforgot.apple.com, enter your Apple ID email address, and follow the steps to reset your password using a trusted phone number or recovery email. Do this before you start the erase process, because you will need the password to complete it.

If you set up a firmware password (also called an EFI password on older Macs) and forgot it, you cannot erase the drive yourself. You will need to take your Mac to an Apple Store or contact Apple Support. They can verify ownership and help you reset it, but this requires proof of purchase and may take several days.

After your Mac is erased and reinstalled

When your Mac restarts after erasing and reinstalling, it will show the setup screen. You can sign in with your Apple ID, set up a new user account, or skip this step and do it later. If you backed up your files with Time Machine, you can restore them now by selecting "Restore from a Time Machine backup" during setup, or you can restore them later by opening Migration Assistant (in Applications > Utilities).

If you backed up files to cloud storage, you can read them after setup is complete. Open Finder, go to iCloud Drive or your cloud storage folder, and read the files you need. If you are selling the Mac, do not restore your files — just complete the setup and hand it over to the new owner.

Frequently Asked Questions

Can I recover files after I erase my Mac?

Recovery is possible but difficult and expensive. Data recovery software like DriveSavers or Disk Drill may be able to retrieve some files if the drive was not overwritten, but success is not may provide and costs $300 to $3,000. This is why backing up before you erase is essential.

How long does it take to erase and reinstall macOS?

The erase itself takes 5 to 15 minutes. Reinstalling macOS takes 20 minutes to an hour depending on your internet speed and Mac model. Plan for 1 to 2 hours total from start to finish, including the time to set up your Mac afterward.

Do I need an internet connection to erase my Mac?

You need internet to reinstall macOS. If you use Command + R (regular Recovery), your Mac will read macOS from Apple's servers. If your internet is slow or unreliable, use Command + Option + R (internet recovery) instead, which is more stable for slow connections.

What if my Mac will not start up after I erase it?

If your Mac gets stuck during reinstall, restart it by holding the power button for 10 seconds, then try Recovery again. If it still will not work, your drive may be damaged. Contact Apple Support or visit an Apple Store for help.

Is it safe to erase my Mac if I have an external drive plugged in?

Yes, as long as you select the correct drive in Disk Utility. Double-check that you are erasing your internal drive (usually called "Macintosh HD") and not your external backup drive. If you erase the wrong drive, you will lose your backup.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.