Whenever a new software version is released for the Mac, such as macOS Sequoia, many Mac users prefer to completely reinstall their Mac using a clean install.
This has many advantages. For example, it will erase the junk from previous versions and you will start with a clean slate. The biggest advantage will be that macOS will feel faster. It is also advisable to reinstall your Mac if you experience problems. Like previous versions, it is possible to use macOS Sequoia to reinstall your Mac.
If Sequoia is already installed
This procedure is intended for Mac users who have already installed macOS Sequoia. Are you still using macOS Sonoma or earlier? Then it is also possible to reinstall it and then update to macOS Sequoia. In addition, you can also directly reinstall your Mac with a macOS installation USB stick.
Clean Install: Reinstall macOS Sequoia
It is important that before you reinstall your Mac, copy any files and documents you want to keep to an external hard drive or an online service such as iCloud Drive, Dropbox, or Google Drive.
- Then restart your Mac
- Enter the key combination immediately cmd⌘ + R out
- Release the keys when you see the Apple logo
- Recovery mode is activated
Do you have a Mac with an Apple Silicon processor, such as the M1 chip? Then you need to activate recovery mode in a different way than the steps above. Turn off your Mac and then hold the power button. Keep holding the button until the ‘Loading Startup Options’ screen appears. Click ‘Options’ and then ‘Continue’.
Completely erase (format) hard drive
- Click on the wifi icon in the menu bar and connect
- Click on Disk Utility ▸ Continue
- Select Macintosh HD – Data in the column
- If necessary, click on ‘Activate’ at the top first
- Enter the administrator/disk password ▸ Unlock
- Then click the minus button in the toolbar to erase the volume
- Select ‘Delete volume group’
- Confirm the deletion
- In the ‘Macintosh HD’ column, select
- Now click on ‘Delete’ in the button bar
It is possible that after erasing the data disk and the volume group, Macintosh HD will also be erased and removed from the list. The result is that only the SSD is visible. You can erase it again by clicking on the ‘Erase’ button bar and then giving it the name ‘Macintosh HD’.
Now you need to choose a format for your hard drive, most likely it is already equipped with APFS. Then you can only choose APFS. Don’t see the option? Then traditional hard drives can choose ‘Mac OS Extended (Journaled)’ and if necessary for the layout for ‘GUID Partition Scheme’. Then enter a name (you can keep the same name if you want) and click ‘Erase’. Your drive will now complete will be erased, once this is complete you can close the disk utility window.
Performing a Clean Install in conjunction with a Fusion Drive
If you have a Mac with an official Fusion Drive, it is best to follow the steps below:
- Turn off your Mac
- Turn on your Mac and immediately press and hold command⌘ + enter pressed
- Release the keys when you see the Apple logo or a spinning globe
- Recovery mode is activated
- If necessary, log in and then click on Utilities ▸ Terminal in the menu bar
- Type
diskutil resetFusionin the Terminal window and then press enter - Type
Yeswhen prompted and confirm with enter
When Terminal reports that the operation was successful, close the window to return to the macOS Utilities window. Then choose Reinstall macOS and follow the onscreen prompts to reinstall your Mac operating system. When it’s done, your Mac will reboot from the Fusion Drive.
More information can be found here on the Apple Support website. Are you experiencing problems? Then you need to perform an internet recovery.
(Re)install macOS Sequoia
Once your hard drive is formatted, you can reinstall macOS Sequoia. In the Utilities window, select Reinstall macOS. Click Continue, then carefully follow the on-screen instructions. In the Disk Selector window, choose the current macOS disk (the one you just erased)—in most cases, this will be the only available disk. Your Mac will now redownload the most recently installed version on your Mac.
All data will be erased
Please note that the hard drive will be completely erased and will be re-installed with macOS. This will delete all (personal) data, applications and files. We emphasize again that it is best to copy all important files to an external hard drive or make an exact copy of your current hard drive with an application such as SuperDuper (how to read in this article).
It has by the way no sense to restore an exact copy or Time Machine backup to your Mac after a reinstall. You will then reinstall all the ‘junk’.
Performing a Clean Install from an Old Software Version
In the article above, we assume that Sequoia is already installed on your Mac and that you have no problem reinstalling the update after erasing. Would you rather install macOS 15 Sequoia directly? Then you will need to use an installation USB stick. How to create and use this can be read in the highlighted article below. After erasing the hard drive, connect the USB stick to your Mac to install macOS.
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