What does a hard reset on Mac do?

A hard reset on a Mac essentially resets the device back to factory default settings and erases all data and settings. It can help resolve issues like crashes, freezes, or slow performance. A hard reset is more extensive than restarting your Mac, and it should only be done as a last resort when troubleshooting. Here’s a more in-depth look at what happens during a hard reset and when you may need to use this option.

How a Hard Reset Works

When you do a hard reset, your Mac starts up from a clean state. All user data and settings are erased from the startup drive, including:

  • User accounts and passwords
  • Apps and program data
  • System settings and preferences
  • Cached and temporary files

Essentially, your Mac will be restored to the state it was in when you first took it out of the box. The operating system gets reinstalled, and any issues caused by software errors or problematic files are eliminated.

It’s important to note that a hard reset permanently erases all information on the startup disk. So before proceeding, you need to back up any files you want to keep by copying them to an external drive. Any data left on the startup disk will be deleted.

When to Use a Hard Reset

A hard reset or reformatting is typically used as a last resort when you have an issue that can’t be resolved through standard troubleshooting.

Here are some examples of when you may want to do a hard reset:

  • Your Mac won’t start up all the way
  • You’ve tried restarting and other basic troubleshooting, but your Mac still runs slow or keeps crashing/freezing
  • An update or new app seems to have destabilized your system
  • You keep getting repeated error messages and can’t use your Mac properly
  • You want to erase all data and settings before selling or giving away your Mac

Essentially, if basic troubleshooting steps aren’t working and your Mac is unusable or unstable, a hard reset clears out any underlying software problems and lets you start fresh.

How to Do a Hard Reset on Mac

The steps to hard reset a Mac will vary slightly depending on the model you have. Here are the general steps to follow:

1. Back Up Important Data

Before erasing your Mac, make sure to back up any important files and data. You can copy files to an external hard drive, upload them to cloud storage, or use Time Machine to backup to an external disk. Back up any data you want to keep.

2. Sign Out of iCloud and Other Accounts

Sign out of iCloud, iTunes, the App Store, and any other accounts you’re signed into on your Mac. This will deactivate anything linked to your accounts before wiping the data.

3. Restart in Recovery Mode

The next steps will restart your Mac into Recovery Mode, which is a special troubleshooting environment. Here’s how to enter Recovery Mode on different Macs:

  • Apple silicon Macs (M1/M2 models): Press and hold the power button until “Loading startup options” appears. Select your language, then choose Options > Continue.
  • Intel-based Macs: Restart your Mac, then immediately press and hold Command + R until you see the recovery screen.
  • Older Macs: Restart while holding Option + Command + R to start up from internet recovery.

4. Erase the Startup Disk

In Recovery Mode, select Disk Utility from the Utilities menu. Choose your startup disk from the sidebar, then click Erase at the top. Give it a name if desired, use Mac OS Extended format, and click Erase to confirm.

5. Reinstall MacOS

With your startup disk erased, you can now reinstall the Mac operating system:

  • On Apple silicon Macs: After erasing, you’ll return to the main Recovery screen. Select Reinstall macOS and follow the prompts.
  • On Intel-based Macs: If you don’t see the macOS installer, go to the App Store in Recovery Mode and download the version your Mac shipped with. Then run the installer.

The reinstallation process will take some time to fully copy files and configure your Mac. When it’s done, you’ll be able to set up your Mac like new.

What to Do After Resetting a Mac

Once your Mac restarts after the OS reinstall, there are a few steps you’ll want to take:

  • Set up your preferences and settings how you like.
  • Install apps from the App Store or other sources.
  • Sign back in to iCloud and other accounts you use.
  • Transfer any files you backed up back to your Mac.

Essentially, you’ll want to personalize your Mac, redownload apps, and restore any files you need. Aside from that, your Mac should hopefully be back up and running smoothly!

Alternatives to Resetting Your Mac

While a hard reset is an effective troubleshooting technique, it should only be used as a last resort given it erases all your data. Here are a couple alternative options to try first:

  • Restart your Mac – Try restarting your Mac before you reset it. This can clear out minor errors.
  • Run diagnostics – Use the built-in Apple Diagnostics tool to check for issues.
  • Repair disk permissions – You can repair disk permissions in Recovery Mode.
  • Remove problematic apps – Uninstall any apps or updates that may be causing instability.
  • Reset NVRAM – This resets certain system settings and can resolve booting issues.

Resetting your Mac should be a last resort, but sometimes it’s your best or only option to get your Mac running smoothly again. Just be absolutely sure to backup your data first!


Here are some key points about what happens when you reset a Mac:

  • A hard reset erases all data/settings and reinstalls the OS.
  • It can fix many system issues and instability.
  • Back up important data before resetting.
  • Sign out of your accounts beforehand.
  • You’ll need to reinstall apps and personalize settings after.
  • Try other troubleshooting steps before resetting.

While frustrating, resetting your Mac gives you a clean slate if you’re experiencing major software issues. Just be prepared to backup data, reconfigure settings, and reinstall software if you do a hard reset.

Pros Cons
Resolves many serious software issues Erases all user data and settings
Can improve system performance Requires reconfiguring personal settings
Fixes problems caused by bugs or incompatibilities Need to reinstall all your apps
Often works when other fixes don’t Takes time to backup data and reinstall software

Related Questions

How is a hard reset different from restarting my Mac?

Restarting simply powers your Mac off and back on again. A hard reset goes further by erasing all data/settings and reinstalling the operating system. So a hard reset provides a much cleaner slate.

Will a hard reset delete all my files and data?

Yes, any files left on the startup disk will be erased after a hard reset. Be sure to copy important files to an external drive before resetting.

Can I choose which data gets deleted in a hard reset?

No, there is no selective erasing. A hard reset will delete all user accounts, apps, files, and settings.

How long does a hard reset take?

It depends on your Mac model, but expect the process to take at least 20-30 minutes. Erasing the disk is quick, but reinstalling the operating system takes time.


Resetting your Mac provides a clean slate that can resolve many software issues and performance problems. But this process erases all your data, so it’s critical to back up any important files first. While frustrating, a hard reset is sometimes the only reliable fix for major system issues. Just be prepared to invest time reconfiguring your settings afterward.