In this article nosotros're going to prove you how to perform a clean install of macOS. There are a number of reasons why you might desire to do a clean install:

  • Y'all might desire to reinstall the operating organization in order to right problems with your Mac - doing a clean install may exist a skilful option if your Mac is running tedious or otherwise misbehaving.
  • Doing a clean install allows you to clear away quondam files that yous might have been accumulating for years before installing the operating arrangement onto a freshly formatted deejay.
  • A clean install is also something you should do before selling your Mac or passing it on. Information technology allows y'all to remove all your data from your Mac and return it to mill settings for side by side person.
  • A clean install is also something many computer users resort to when they are trying to get rid of a virus (although there is a lot of debate nigh whether there are viruses on the Mac).

Whatever your reason, a clean install of macOS might solve a lot of problems.

However, things take changed in contempo years that hateful that a clean install may not be necessary, so we volition start by explaining why yous might not need to do a clean install on your Mac.

Yous should also keep in mind that there are multiple means to do a make clean installation of macOS. The traditional manner was to brand a bootable copy of the macOS installer on a USB stick and then reformat your drive earlier installing the bootable copy on to your Mac. At that place is likewise an fifty-fifty simpler method that allows you lot to use macOS Recovery to reinstall the Mac operating system over the spider web (we accept a carve up tutorial about doing a clean install of macOS using Recovery). Plus, if yous are running macOS Monterey on a M1 Mac or an Intel Mac with a T2 flake so at that place is a new setting in System Preferences that makes wiping your Mac easier than ever. We'll run through all of these methods beneath.

Should I do a clean install on my Mac?

In the past information technology was helpful to reinstall the system if you wanted to correct some Mac problems, but today this solution doesn't brand every bit much sense.

Since macOS Big Sur, macOS has its home on its own volume, which is both read-only and cryptographically signed and sealed (referred to as a Sealed System Volume). This seal is stored either in the T2 chip of the newer Intel Macs or in the Secure Enclave of the Apple tree M1.

Each component of the organization is signed in hierarchical order, and any change to a component would also invalidate the seal that represents the top level. For further security, these Macs also exercise non kickoff direct from the system volume, but from a snapshot of the system. And snapshots cannot be changed, even by the system itself.

So macOS itself cannot be inverse by any software that yous install equally a user. Should a problem occur with macOS during a restart, perhaps because a storage space on the SSD is defective and thus a organisation component is no longer intact, this will exist recognised by the startup process since the seal will at present be invalid. Should this happen you will have to reinstall the system.

However, if your Mac boots upwards without consequence so it indicates that there are no bug with the system. As long as your Mac works (which can be adamant on the basis of the seal), the Mac is considered to be in working guild as it complies with Apple tree's specifications.

For that reason, even if you do encounter issues on Macs with T2 bit or Apple Silicon while running macOS Big Sur or macOS Monterey, it makes no sense to reinstall the system yourself.

For those who want to practise a clean install and so that no leftovers that vest to an old system are carried along, this no longer applies because none of this information is carried over. All components are checked after installation, then signed and finally the entire system sealed again. Again, the seal guarantees that everything is fine and that nothing untoward has crept in.

However, there is one component of the system software that is not installed on the read-only organisation volume. All other user-installed programs reside on the volume with the user data, including Safari. This means Apple can offer a separate update for the browser and WebKit, then that yous do not take to reinstall the whole system each fourth dimension.

In the case of Safari and other apps in that location can be benefits in cleaning up your Library folder since it may yet contain remnants of quondam applications yous no longer apply.

If you feel that y'all have a lot of this sort of crud on your Mac then cleaning your bulldoze could be useful, just be prepared that it tin can exist a risky business organization and you may end up deleting something of import. Beware that a clean install tin crusade more problems that it fixes.

Yous might adopt to utilize an awarding like CleanMyMac Ten from MacPaw (£34.95/$39.95 a year, free trial), or one of these alternatives: Best Mac Cleaner App.

If you are happy to accept the risk and yet want to wipe your Mac and reinstall macOS - which you should definitely do if yous are selling or passing on your Mac - read on!

How to wipe your Mac and reinstall macOS

As we explained in a higher place, there is more than one mode to wipe your Mac and reinstall macOS:

  • Make a copy of the macOS installer on a USB stick, reformat your bulldoze so install the macOS on to your Mac from the installer.
  • Use macOS Recovery to reinstall macOS the spider web.
  • Use the new Erase All Content and Settings choice setting in Arrangement Preferences (available if you are running macOS Monterey on a M1 Mac or an Intel Mac with a T2 bit).

Non but are in that location three different methods (which we'll run through below) the methods depend on the version of macOS that you lot are running.

In that location is also the even trickier business of installing a make clean copy of an older version of macOS on your Mac (Large Sur, Catalina, Loftier Sierra, Sierra, El Capitan, Mojave, Yosemite or an even erstwhile version of Bone X). Speaking of which, if an old version is what you're looking for, it may be worth taking a wait at another article where we focus on that entirely: How to download and install old versions of OS X on a Mac.

Earlier you lot brainstorm...

Nosotros recommend that you brand a support, just in case something goes wrong. Full instructions here: How to back upwardly a Mac.

Notation that with regard to backups, y'all probably won't want to recover a Time Machine fill-in if you don't want to copy over all the setting and preferences associated with your old system. You could alternatively sync all your Documents and Desktop with iCloud rather than run a full backup, but make sure that everything you lot need is in the cloud and exist aware that you may lose system setting and applications.

Ready? Permit'south become started.

How to make clean install macOS Monterey

How to clean install macOS Monterey

Earlier the inflow of Monterey it was necessary to create a bootable USB drive or use Recovery Mode to wipe your disk. However, with Monterey Apple has made it piece of cake to get a factory-fresh installation.

In that location is a new Erase All Content and Settings selection in the Arrangement Preferences menu of Monterey that will allow you to reset your Mac to factory settings without having to piece of work through the many steps to wipe and format your drives.

Likewise as macOS Monterey, you need to accept a M1 Mac, or an Intel Mac with a T2 chip inside.

These Intel Macs have the T2 security chip:

  • MacBook Air from 2022
  • MacBook Pro from 2022
  • Mac mini from 2022
  • iMac 27-inch from 2022
  • iMac Pro
  • Mac Pro from 2022

If you accept the Erase All Content and Settings selection in Monterey and so yous can hands wipe your system, remove all your data and user-installed applications and start from scratch. Here's what you need to do:

  1. Open up System Preferences.
  2. Click on System Preferences in the menu bar at the top of your screen.
  3. Click on Erase All Content and Settings.
  4. Enter your countersign.
  5. (You'll exist reminded to do a backup with Time Auto before you brainstorm deletion - but you can skip that pace.)
  6. A window volition show you what will exist deleted, including Apple ID, Touch on ID, accessories, and Find My settings.
  7. Finally you will need to log out of your Mac and all related services using your Apple ID.
  8. Before your Mac is erased you receive a terminal warning, and then if you lot accept 2nd thoughts at least you can stop at this point! Erase Mac Monterey
  9. Having clicked the second Erase All Content & Settings your Mac will restart. Eventually you will see a black screen while it restarts.
  10. Once your Mac restarts you lot can go through the steps to fix it upward equally new, or y'all can get out it at this stage for the next owner to fix. Merely turn the Mac off kickoff.

How to practise a clean install via Recovery

How to do a clean install via Recovery

We explain how to reinstall macOS via Recovery here: How to reinstall macOS, just we will summarise the steps here.

How yous enter recovery mode depends on the Mac y'all own.

If you want to enter recovery style on an M1 Mac you need to press and hold the power button when you start upwards your Mac and go on to press and hold the button until you see a startup options window appear with an Options icon. Select Options and click Continue.

To enter Recovery on an Intel Mac press Command+R.

  1. One time Recovery starts up you'll see a macOS Utilities window with options to Restore From Fourth dimension Machine Backup, Reinstall macOS [version], Safari (or Get Assist Online in older versions) and Disk Utility. If you want to wipe the Mac earlier reinstalling choose Disk Utility.
  2. Run through the steps to erase your Mac as detailed in the How to reinstall macOS guide.
  3. Subsequently you have erased your drive click on Disk Utility > Quit Disk Utility. Or just Control + Q.
  4. At present cull Reinstall macOS from the options.
  5. Wait while macOS is reinstalled. Expect this to take a while.

How to make clean install macOS using a bootable USB

How to clean install macOS using a bootable USB

Now for the method that involves using a bootable USB with the macOS installation on it. This might be the best method if you already have the installation files downloaded and don't want to wait for hours for Recovery to download the files.

Before you brainstorm y'all'll demand the following:

  • A 15GB or larger removable USB flash drive to agree the installer file for our chosen version of macOS. (We're going to erase it, so brand sure it doesn't contain any valuable data.)
  • Admin privileges for the Mac.
  • A support, just in case something goes wrong.

Pace one: Format the external drive

Step 1: Format the external drive

We're going to re-download the installer file for our called version of macOS and store information technology on a USB stick or external drive. But earlier you practice that you tin can set the USB drive by reformatting it.

Here's how to format your USB drive correctly:

  1. Plug in the USB drive.
  2. Go to Applications > Utilities.
  3. Open Disk Utility.
  4. Select the drive and click Erase. (The proper name of the disk needs to be "Untitled", if the Terminal commands below are to work, then rename information technology if necessary.)
  5. Select Mac OS Extended (Journaled) as the format type.
  6. Choose GUID Partition Map from the Scheme options (if you lot don't meet this you are in the incorrect view - you demand to select the external drive, not the container below it).
  7. Click Erase.
  8. Disk Utility will create the partition and set the bulldoze (it tin can take a while).
  9. Click Washed.

Step 2a: Become the macOS install file

Step 2a: Get the macOS install file

If y'all're reinstalling the latest version of macOS, or installing a new version of macOS, the next footstep is relatively like shooting fish in a barrel although the process for obtaining the installer will be different.

If you are currently running Big Sur and want to do a make clean install of macOS Monterey (once it arrives) then y'all tin download the installation package via System Preferences.

  1. Open System Preferences.
  2. Choose Software Update.
  3. Download the Monterey install files.

If, on the other hand, you want to reinstall Large Sur and are already running Big Sur the best manner to access the installer for Large Sur is via the Mac App Store. Here's a link to Big Sur on the Mac App Store. If it's Catalina you want y'all can get that here. Alternatively open up Mac App Store and search for the version you want.

Once you have located the version of macOS you want on the Mac App Shop follow these instructions:

  1. Striking Download or Get (depending on the version of the Mac App Store you are using).
  2. You may get a warning message at this point, telling you that this version of macOS 'is already installed on this computer. Would you similar to go on?' Click Continue.
  3. Enter your Apple ID and password.
  4. The Catalina install files volition showtime to download.

The installer file volition be multiple GB. Big Sur is 12.6GB, for example, so expect downloading to accept a while.

The next footstep is worth highlighting for what you shouldn't do, rather than what you should practise:

  1. When the macOS installer has finished downloading the installer will launch automatically, but nosotros don't want to use information technology yet so don't click to start the installation!
  2. Press Command + Q to quit out of the installer.
  3. Find the installer file (it will exist located in your Applications folder, or y'all could search for information technology using Spotlight (command + Space and start typing Monterey, Catalina or Big Sur).

If you but want to install Monterey you can skip the side by side step where we'll be showing how to dig upward the installer file for an older version of macOS or Mac OS 10.

Step 2b: Go the install file for an older version of macOS

Step 2b: Get the install file for an older version of macOS

For older versions of macOS and Mac OS X it'south a flake more difficult to become the install file: Apple doesn't offer downloads of outdated Os versions through the normal shop front end, and searching for the name won't find what you're looking for.

We have a detailed guide to getting older versions of macOS here, only we will explain what y'all need to do below.

Depending on the version of macOS yous are running, the installers for some versions of macOS tin can be plant in the Purchased section of the App Store.

Log into the Mac App Store with the Apple ID y'all used and click Purchased in the carte bar along the top. Scan down the listing of apps you've purchased or download for complimentary (which is in order of when you downloaded them) and find the proper name of your chosen version: El Capitan, Yosemite or whatever. Click download.

However, there are a few reasons why this may not work for y'all:

  • If you have already installed Mojave, Catalina or Big Sur on your Mac you cannot hands search for onetime versions of macOS from the Mac App Store.
  • Yous won't observe the version of macOS your Mac shipped with in the Purchased section of the App Store.
  • And yous won't find versions of macOS in the purchased section if yous never installed that version.

However, luckily information technology is still possible to get hold of some versions of macOS if you are running a newer version than Sierra.

  • Big Sur is on the Mac App Store hither.
  • Catalina is on the Mac App Store here.
  • You can become macOS Mojave via this link.
  • Download High Sierra here.
  • Sierra is here as a direct download.
  • El Capitan tin be downloaded from this link.
  • Yosemite is available hither.

If yous click to discover Catalina, Mjave or Loftier Sierra and the page doesn't open up in the Mac App Shop try a couple of things: Make sure that the Mac App Store is closed earlier you click the link; Cutting and paste the link into Safari.

Every bit in the step higher up, in one case you have downloaded the installer don't run information technology - simply shut the installer if it opens.

For more advice on getting agree of even older editions of Mac OS, seeHow to get one-time versions of OS Ten.

Pace iii: Create a bootable USB deejay

Step 3: Create a bootable USB disk

Side by side we need to turn out USB bulldoze into a bootable USB disk so that nosotros can use it to install a new copy of macOS on our Mac later on we have reformatted it (that stride will come after in this tutorial).

We've got full instructions on How to make a bootable macOS install drive in a different article, just we'll run through the basics here.

We're going to create the bootable drive using Terminal, which yous can open on your Mac by pressing Command + Infinite bar and typing Terminal.

Connect the USB bulldoze that you formatted before to your Mac. Make sure information technology's called Untitled - rename it if necessary (this will assist you enter the correct text in Terminal in the next steps).

Creating a bootable installer has been pretty like shooting fish in a barrel since the arrival of Mavericks in 2022 thanks to the Terminal command createinstallmedia that arrived in that version. Here's how to use information technology (note that the name of the version of macOS will depend on which version you lot are installing):

  1. Open the Terminal awarding on your Mac (notice it by searching using Command + Infinite and typing Terminal)
  2. Now copy and paste the following text into Last (This text is for Large Sur - we include the text needed for the other versions of macOS in this article). When yous cut and paste the following text into Terminal practise check that it maintains the -- every bit we have heard of people pasting in the -- and it converting to –)
    sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resource/createinstallmedia --volume /Volumes/MyVolume (where MyVolume is the proper noun of the external bulldoze you are using - information technology could be Untitled)
  3. Printing Return.
  4. Enter your password (you lot won't see the password appear).
  5. Press Render once again.
  6. Terminal will warn that it is nigh to erase the drive. If y'all want to keep printing Y and then Render. The process can take a while, you'll see "Erasing Disk: 0%… 10%… 20%… 30%…100%…
  7. Adjacent Last will spend a few minutes copying the installer file to your drive. "Copying installer files to disk… Copy complete" then on will announced in the Final window. Again, this can take a while - it took our Mac ages to go from 0% to x%...
  8. When the bootable drive is prepared you lot will see the discussion Washed. It tin can take a while.

At present y'all have the installer on the external drive you can use that to install copies of macOS on multiple Macs - which could exist helpful if yous are admin for a lot of systems.

However, if you are reading this because you desire to practise wipe your Mac and do a clean install, read on...

Step four: Wipe your Mac

Step 4: Wipe your Mac

Now nosotros are ready to install the copy of macOS from the installer drive on our Mac. If you want to do a fresh installation (and completely wipe your Mac) information technology's time to reformat your Mac'southward start-upwards drive.

Here's how to practice a fresh installation of macOS if you aren't already running Catalina or Big Sur.

  1. Connect your boot drive.
  2. Start up - or restart - your Mac while holding down the Option key (also known as Alt). This will have you to Startup Managing director.
  3. Cull to install your called version of macOS from the external bulldoze.
  4. Select Deejay Utility.
  5. Select your Mac's beginning up disc, probably chosen Macintosh Hard disk or Dwelling house.
  6. Click on Erase.
  7. Wait for your startup disk to be formatted.
  8. Become back to the main Utilities menu and choose Install macOS.
  9. Choose your startup drive as the location to install macOS.

In one case installation is complete, you can restore apps and settings from your backup, or download them again manually.

How to erase your bulldoze in Catalina or Large Sur

Note: if you are running macOS Catalina or Big Sur yous will have two volumes: Macintosh HD and Macintosh HD - Data. If you want to exercise a clean install of Catalina or Large Sur over an existing installation of Catalina you volition need to first delete the Macintosh Hard disk drive - Data volume. We cover how to do this in more detail here: How to reset and wipe a Mac.

Macintosh HD - Data in Catalina/Big Sur is where your data is stored separately to the macOS installation.

  1. Either click on the - push or get to the menu and choose Edit > Delete APFS volume.
  2. You will come across a message alarm you that this will permanently erase your data. Click on Delete. Do not choose Delete Book Group.
  3. Expect while the book is deleted.

Then you tin move onto deleting your Macintosh Hd book equally above.

Stride 5: Install macOS

Step 5: Install macOS

Now you lot can use your bootable installer to practise a clean install of macOS on your wiped Mac.

The process for installing the Os from the bootable installer is slightly different if you have an M1 Mac (also known every bit Apple Silicon) or an Intel processor inside your Mac. Nosotros'll run through both methods.

In both cases you volition need to accept your Mac connected to the Internet. It also needs to be uniform with the version of macOS you are trying to install (yous tin can't install a macOS older than Big Sur on a M1 Mac).

How to install macOS from a bootable installer

If y'all have an Intel-powered Mac here's how to install macOS from a bootable installer:

  1. Plug in your bootable installer
  2. Turn off your Mac.
  3. Press and concur Selection/Alt while the Mac starts up - continue pressing the cardinal until you see a screen showing the bootable volume.
  4. Cull the bootable installer book.
  5. Click Continue.
  6. Select Install macOS from the Utilities window that appears.
  7. Click Continue.
  8. Now follow the onscreen instructions to do your clean install.

If you have an M1 Mac hither's how to install macOS from a bootable installer. Equally we mentioned above, y'all tin can't install a macOS older than Big Sur on a M1 Mac.

  1. Plug in your bootable installer
  2. Turn off your Mac.
  3. Press the power button to turn on the Mac - but proceed information technology pressed until y'all see the startup options window including your bootable volume.
  4. Cull the bootable installer volume.
  5. Click Continue.
  6. The macOS installer should open - when information technology does follow the onscreen instructions to practise the clean install.