Last Updated on Aug 24, 2023
In most cases, upgrading your macOS to a newer version will suffice. However, there comes a time when you just have to erase and install macOS on your Mac. To clean-install macOS, you first wipe your Mac clean.
Several things may require you to install macOS, such as a virus or malware attack, software errors, or when you need to resale the Mac. In either case, there are multiple ways you can erase and install macOS Ventura or Sonoma.
Throughout this guide, you’ll learn what a clean install is, why you may need to clean-install, and the different methods you can use.
What Is Clean-Install MacOS?
Clean is a software installation method whereby the previous version of the software is erased from the Mac. In so doing, any other data on the computer is wiped out alongside software files. The alternative to a clean-install is upgrading the software—whereby some elements of the previous installation are retained.
The clean installation also refers to a scenario where software is installed for the very first time. Following a clean install, the hard disk on your Mac will only contain the macOS operating system. When you clean-install macOS Ventura or Sonoma, the existing macOS installation and user files are erased. As such, it is advisable to first back up your Mac before attempting to clean install macOS Sonoma or Ventura.
When Should You Clean-Install MacOS?
A clean macOS install or upgrade is a time-consuming and rather boring undertaking. No wonder most Mac users prefer upgrading macOS to clean and install the operating system (OS). Even so, there are cases when a clean install of the OS is necessary.
So, why would you need to clean-install macOS on a Mac?
- Corrupted Software Files
Sometimes, corrupted macOS files can make it impossible for you to upgrade the operating system. In other cases, the Mac fails to boot into macOS recovery. This, in turn, makes it impossible for you to reinstall macOS using the conventional method.
In such a case, you just have to wipe the Mac clean, then install macOS afresh from the Recovery mode or use a bootable drive.
- Just Before or Give Your Mac Away
If you are about to resale your Mac, it is best to ensure you don’t leave any personal data on the computer. To avoid giving away your personal information alongside the Mac, you should clean install macOS—hence, wipe the Mac clean.
- Reduced Mac Performance
Has your Mac become considerably slower and sluggish? If so, a conventional in-place upgrade may or suffice. To speed up the Mac, you should clean install macOS on the Mac.
- Virus or Malware Attack
Some viruses just won’t go away, regardless of what you do to remove them from your Mac. Others may damage your macOS files beyond repair. If you wish to resolve the problem once and for all, just clean install macOS on your Mac.
Regardless of why you want to clean install macOS, you should first backup your Mac. Where possible, it is advisable to use Time Machine on Mac, as illustrated below.
How to Backup Your Mac Using Time Machine
If you don’t want to lose your data on Mac, create a backup before erasing it. In this regard, you may need to back up files that don’t comprise the macOS, such as documents, photos, music, and apps on your Mac.
If turned on, Time Machine will automatically create a backup for your Mac and then update the backup hourly, daily, and even weekly. Again, Time Machine also saves local snapshots that you may use to recover certain files, even when the backup disk is not connected.
In this regard, Time Machine creates such snapshots hourly and saves them on the same disk as their original file copies. Local Snapshots created by Time Machine are normally saved for 24 hours before it is disregarded.
Note: Time Machine Local Snapshots can only be created on disks using the Apple File System APFS).
This being the case, you can easily recover accidentally deleted or altered files on your Mac using Time Machine. Despite this convenience, you should create a backup for your Mac on an external drive, time capsule, or a drive on your network.
To backup a Mac with a Time Machine:
- Connect an external disk to your Mac—should at least have the same capacity as the primary volume on your Mac.
Note: If you back up a Mac running macOS Monterey or later, you can only restore the backup files on a Mac running macOS Big Sur or later.
- From the Menu bar on your Mac, click on the Time Machine icon then select the Open Machine Settings option.
If you cannot find the Time Machine on the Menu bar, click on the Apple icon to reveal the Apple menu. Navigate to System Settings and then click on the Control Center-+located on the sidebar. Now scroll down until you find the Time Machine option and select it.
Finally, expand the pull-down menu and select Show in Menu Bar. You can now find the Time Machine icon on the menu bar.
- Click on Select Backup or Select Disk and check whether the backup disk you connected in step #1 above is displayed. If not, click on the Add (+) button. Now, find the storage drive on your Mac and select it.
Note: Time Machine will not back up the apps or files installed on your Mac during a macOS installation.
- If prompted, confirm the choice you made in step #3 above.
- Should you want to customize your Mac backup, click the Options button, from here, you can select the storage locations you may want to exclude from the backup and even encrypt the backup.
- Once you are done selecting your backup options, click on the blue Done button. Finally, you need to allow Time Machine enough time to finish backing up your Mac.
How to Clean Install macOS Ventura and Sonoma on a Mac
Having decided that it is time to erase all the data on your Mac and factory reset the device, you must be wondering how to go about it. Well, not any longer, discussed below are the top 3 methods you can use to wipe and fresh install macOS on your Mac:
Method 1: Erase and Reinstall macOS Ventura in macOS Recovery
All Mac computers feature a built-in recovery system referred to as macOS Recovery. Booting your Mac into the Recovery mode allows you to accomplish such tasks as restoring your data from Time Machine backups, reinstalling macOS, repairing the internal storage device, setting security options, and restoring Mac to default settings, among other things.
You can also use macOS Recovery to erase and clean install macOS Sonoma, Ventura, and any other version for that matter.
Note: Erasing your Mac will get rid of all the information currently saved on the computer—it goes beyond just replacing the operating system files. As such, you may need to back up the Mac before you start, as illustrated above.
Once you are ready, these steps will guide you on how you can use macOS Recovery to erase and clean install macOS:
Step 1: Erase your Mac Using the Erase Assistant
By default, macOS offers you two main ways to wipe your Mac clean:
- Disk Utility
- Erase Assistant
Added to macOS recently, in 2021, the Erase assistant happens to be the more intuitive and easy-to-use option of the two. Unfortunately, this option is not available on all Macs—only the Macs powered by the Apple Silicon processors and the Intel-powered Macs that have Apple’s T2 security chip have the Erase Assistant functionality.
Additionally, you need to be running macOS 12.0 Monterey or a later version on your Mac to access this option. If your Mac meets these two conditions, you can use the Erase Assistant to:
- Reset the Mac to factory settings
- Erase the Mac before a clean installation of macOS –This operation removes all the apps, content, and settings on your Mac.
What Can You Accomplish with the Erase Assistant
If you happen to have the Erase Assistant option on your Mac, you can use it to accomplish the following tasks:
- Turn off Activation Lock and Find My features such that the erased Mac can no longer be associated with you.
- Sing you out of all Apple services like the iCloud cloud storage
- Erase all the content, apps, and settings on the Mac, without having to reinstall macOS
- Remove all user accounts and their associated data from the erased Mac.
- Erase all the Volumes on your Mac—if you happen to have used Boot Camp Assistant to install Windows on your Mac, running Erase Assistant will erase the BOOTCAMP volume as well.
- Erase all the user accounts on the erased Mac along with their user data.
Now that you know what Erase Assistant does, how can you use it to erase a Mac?
- Click on the Apple logo to open the Apple menu.
- Select System Settings from the Apple menu.
- Navigate to the General tab by clicking on it from the sidebar—you may have to scroll down to find the General option.
- Now click on the Reset or Transfer button that appears on the right.
- Choose the Erase All Contents and Settings option.
Finally, you need to review the items that Erase Assistant will remove as displayed on your display. If the Mac being erased has multiple user accounts, just click on the arrow adjacent to any of the account names to review the items.
- If you are comfortable removing the listed items, click on the Continue button to initiate the Erase process. Just follow the on-screen prompts to complete the process.
Note: If the macOS version installed on your Mac was altered after installation, Erase Assistant cannot Erase the Mac as is. In such a scenario, you are likely to get an alert telling you that you first need to reinstall the macOS before erasing it.
To fix this issue, simply reinstall the macOS on your Mac, and then use the above-described procedure to wipe it using Erase Assistant.
Step 2: Clean Install macOS Sonoma or Ventura on Your Mac
With the Mac completely erased, you now can proceed to clean install your preferred macOS version. To begin with, ensure that the Mac is connected to a stable and secure network. If you are clean installing macOS on an Apple laptop, keep it plugged in throughout the process.
Other than that, the procedure for clean installing macOS depends on the processor used on your Mac model, as explained below:
- Apple Silicon Macs and Intel-Based Macs that Have the Apple T2 Security Chip
If yours is such a Mac, follow these steps to clean install macOS after erasing the Mac:
- Restart the Mac then launch the Apple menu—by clicking on the Apple logo.
- From the Apple menu, select the Shut Down option and immediately press and hold the Power button. Keep the power button pressed until the Loading startup options screen comes up.
- Now select Options then click on the Continue button. This should take you to the recovery menu.
- Click the Reinstall MacOS [your version] from the Recovery app window.
- Click on the Continue button and follow the on-screen prompts to complete the installation.
- For Intel-Based Macs That Don’t Have the Apple T2 Security Chip
If you are using an Intel-based Mac that does not have the Apple T2 Security Chip, use this procedure instead:
- With the Mac powered on, click on the Apple logo to open the Apple menu.
- Select the Restart option and immediately press and hold the R + Command keys at the same time. This should boot your Mac to the Recovery app window.
- Click on the Reinstall MacOS [your version] option then click Continue to initiate the installation. Thereafter, you need to follow the on-screen prompts to complete the installation.
In either case, wait until the installation process is completed and then click the Done button.
Method 2: Wipe and Reinstall macOS in Recovery
If your Mac does not have the Erase Assistant, and you would like to clean install macOS Ventura without USB, the macOS Recovery will come in handy. In this case, the objective is to boot your Mac into Recovery mode and manually erase its drive.
Just as is the case with method #1 above, this method also erases all the data on the Mac, including network settings, user accounts, folders, and files. This being the case, you should log into the Mac and attempt to back up your data before everything is erased.
You may also need to record your network settings somewhere. This way, you’ll have an easy time setting up your network connection after the installation. Before you get started, ensure that your Mac is connected to the internet.
Having done all that, follow these steps to clean install macOS Ventura or Sonoma in Recovery mode:
Step 1: Boot the Mac into an Installer or Recovery Mode
The procedure for booting a Mac into recovery mode varies from one model to another depending on the processor. This is how it should be done:
- For Apple Silicon (M1 &M2 Chip) Macs
- Restart the Mac and immediately press, and hold the power button. Release the power button only when the startup options window comes up.
- Click on the Options icon then click the Continue button.
- For Intel-Based Macs
- Restart your Mac then press and hold the R + Command key combination right away. Keep holding the two keys until you see the Recovery app window.
Note: If your Mac fails to boot into recovery, it is probably missing the recovery partition. In such a case, you can still enter recovery mode by booting into the Network Recovery mode instead.
To do this, restart the Mac and immediately press, and hold the Shift + Command + R keys simultaneously. Provided that your Mac is connected to the internet, this operation should automatically download the missing partition and then boot into recovery mode.
Step 2: Securely Wipe the Drive on Your Mac
Having successfully booted your Mac into recovery, you can now proceed to erase its drive. The following steps will help you accomplish that:
- Click the Disk Utility app from the Recovery menu and then click the Continue button.
Note: If the Disk Utility app is not displayed on your Recovery menu, click on Utilities instead, then select the Disk Utility option.
- The Disk Utility window will display a list of the volumes (hard disks) on your Mac. Click on your primary volume (usually the Macintosh HD drive) to select it. Next, click the Erase button from the toolbar.
Note: If you happen to be erasing a mechanical drive on your Mac, click on Security Options instead. If your Mac has a solid state drive (SSD), skip this part as SSD drives can securely erase by leveraging TRIM.
- Now you’ll be required to give the erased drive a name—for consistency, type Macintosh HD into the Name field.
- Click on the Format field to bring up a pop-up menu. Select the APFS option from this menu.
- Click the Erase to start the process. If your Mac shows an Erase Volume Group button, click on it instead.
Once the Erase process is complete, click on the Done button. Finally, navigate to Disk Utility > Quit Disk Utility. Just like that, your Mac is not ready for a clean installation of macOS Sonoma or Ventura.
Step 3: Clean Install macOS on Your Mac
To clean install macOS on your Mac, just boot the Mac into recovery mode then reinstall macOS. This is how it should be done:
- Boot your Mac into recovery mode as explained in step #2 of Method #1 above.
- From the Recovery menu, click on the Reinstall macOS Ventura—or whichever macOS version is displayed.
- When asked which drive you’d like to install the OS to, select the Macintosh drive you named in step#2 above.
Once the installation begins, just follow the on-screen prompts to complete the process.
The progress bar will show you how far the process is from completion at any given time. The process may take a considerable whole to complete, and the Mac may restart multiple times during the installation.
Method 3: Using the Erase All Contents and Settings Option in System Preferences
Starting with macOS Monterey, Apple introduced the Erase all Content and Settings for Apple Silicon Macs and Intel-based Macs that feature the T2 chip. You can use this feature to easily and securely erase all the data, settings, and apps on your Mac and keep the currently installed operating system.
Prior to this invention, you just had to create a bootable drive or boot into recovery mode for you to erase Mac drives. With the Erase All Contents and Settings option, the manufacturer made it even easier for you to reset your Mac to factory settings.
If you have the Erase All Contents and Settings option on your Mac, use the following steps to factory reset the Mac:
Step 1: Find the Erase All Content and Settings Option
This option is located in your Mac’s System Preferences. The right procedure for accessing the Erase All Content and Settings option varies from one macOS version to another, as explained below:
- For macOS Ventura
If you are running macOS Ventura on your Mac, click on the Apple logo. From the Apple menu that comes up, select the System Settings option. Next, go to the General tab, by clicking on it from the sidebar.
Now click the Reset or Transfer button towards the right side of the window. Finally, you need to find the Erase All Content and Settings and click on it.
- For macOS Monterey
The procedure for accessing the Erase All Contents and Settings is a little different on macOS Monterey. In this case, you should launch the Apple menu in the corner of your desktop. Next, select the System Preferences option.
Now select Erase All Content and Settings from the System Preferences menu—positioned on the menu bar.
Step 2: Sign In and Backup the Mac
Sign into your Mac using the administrator credentials when prompted to do so—enter your password then click the OK button. If the system asks you to back up your data before erasing, you should launch Time Machine and create a backup, as illustrated above.
At this point, you should see a window displaying the items that will be erased, such as your Apple and Touch ID, Find My settings, and accessories. Click on the Continue button to consent to have the listed items erased.
You’ll then get a prompt asking you to confirm the operation, just click on the Erase All Content & Settings button to confirm. After you have confirmed, your Mac will restart and display either a progress bar or a black screen.
Note: you may be asked to turn on an accessory, such as a keyboard or mouse, if your Mac needs to connect to the accessory. If you get this request, turn on the requested accessory and wait for it to connect.
If the accessory doesn’t pair to your Mac within 30 seconds, turn the accessory off and then on once again. If your Mac needs to reconnect a Bluetooth keyboard, you’ll be asked to select your preferred language.
Step 3: Connect the Mac to the Internet
Now, your Mac will attempt to connect to the internet. If it fails, you may be asked to either attach a network cable or choose a Wi-Fi network. To select a Wi-Fi network, simply click on the Wi-Fi menu—situated on the upper-right corner of the display.
As soon as your Mac established a connection to the internet, it will activate.
Note: If you were clean installing macOS on your Mac before selling or giving it away, you should leave it in this out-of-box state. In this case, you should just long-press the power button until it goes off. Otherwise, you can go ahead and set it up afresh, as described below.
When you get this screen, click on the Restart button. After restarting, your Mac opens a Setup Assistant. This will take you through the setup steps as though you were setting a brand-new Mac for the first time.
Method 4: Clean Install macOS Using a Bootable USB Drive
Would you rather clean install macOS from a USB drive? Well, this is also possible. In this case, you first need to erase the drives on your Mac before you can clean install macOS on a Mac. You can use any of the above-described methods to clear your Mac to pave way for a clean install.
Once you have erased the Mac, use these steps to create a bootable disk and boot from it:
Step 1: Download the Installer File for macOS
First, you must download the installer file for the macOS version you wish to clean install. Be sure to download your macOS installer files from the App Store or the official Apple website. To clean install macOS from a USB drive:
Step 1: Download the Installer File for macOS
Get the installer file for the macOS version you need to clean install. On a working Mac, follow these steps to download the installer macOS installer file:
- Launch the App Store by clicking on its icon.
- Navigate to the Purchases tab on the App Store window—you can find your previously downloaded upgrades here even though you no longer need to pay for them.
- Find the macOS version you wish to reinstall and select it. Next, click on the Install button next to the macOS version you just selected.
By default, the chosen macOS installer file will download to the Applications folder on your Mac and is named macOS [Version Name].
Step 2: Create a Bootable macOS USB Drive
To create a bootable USB drive using the macOS installer file you just downloaded, you need to run a few commands on the Terminal. To do this:
- Insert a USB drive into a USB port on your Mac—preferably a 16 GB USB drive.
- Open a new Terminal window from the Utilities folder on your Mac.
- To get the Volume name, run the following command on Terminal:
Press the return key to run it.
- Depending on the macOS version you are working with, enter the following command into the Terminal window:
For macOS Sonoma: sudo /Applications/Install\ macOS\Sonoma.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume
For macOS Ventura: sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume
Note: Volume in the above commands should be the name of the USB Drive so change it to the name of your USB drive.
- Once you’ve entered the code into the Terminal, press the Return key to run it
- Enter the admin password when prompted to do so, then press the Return key.
You should now get a prompt asking whether you wish to erase your USB drive. When you do, press the Y keys to consent and then press Return to run the command. The system should now display a progress bar that shows the percentage of the drive that has been erased.
Allow the system-bought time to erase the disk—the progress bar gets to 100%–before doing anything else.
- At this point, you may get a prompt asking you to grant access to your removable USB drive. To consent to this request, click on the OK button.
When done, your removable drive should have the same name as the macOS installer file you downloaded. When the process is completed, just exit Terminal and eject the USB drive.
Now you have created a bootable drive that you can use to clean install macOS on your Mac.
Step 3: Erase the Current Disk By Booting to Recovery Mode
Execute steps #1 and #2 as described in method #2 above to boot your Mac in Recovery Mode, and Erase the primary volume using Disk Utility. Once your Mac had been erased, the following step will help you clean install macOS from the bootable USB drive you just created.
Step 4: Boot the Erased Mac from the Bootable Drive
To clean install macOS Ventura or Sonoma—depending on the version you used to create the bootable disk—you should: :
- For Apple Silicon Macs
If your Mac run on an Apple Silicon processor, plug the bootable drive into a USB port on the Mac and connect the Mac to the internet. Next, long-press the power button until the Utilities window appears.
Now select the bootable USB drive from the displayed options and then click the Continue button. Follow on-screen prompts to complete the installation process.
- For Intel-Based Macs
If yours is an Intel-powered Mac, insert the bootable drive into a USB port on the Mac. Ensure that the device is connected to the internet. To reinstall macOS from the bootable USB drive, long-press the Option key on the Mac until a list of volumes appears.
Select your bootable USB drive from this list of volumes and then press the Return key. Now you only need to follow on-screen prompts to complete the process.
Clean installing macOS refers to installing the operating system onto an erased drive. To clean install any version of macOS, you first need to remove everything from its drives. You can accomplish this using different methods as illustrated above.
Regardless of the reason behind the installation, the above-described methods will help you clean install macOS and restore your Mac to factory settings.