Select “Macintosh HD” as the destination disk to install MacOS Big Sur onto, then choose “Install” to begin the process of installing a fresh version of MacOS Big Sur.

Back at the ‘macOS Utilities’ screen, select “Install macOS” from the options available.

When Disk Utility has finished formatting the disk, quit Disk Utility.

Choose “Macintosh HD” as the disk name (or pick another if you’re so inclined), then go to “Format” and select APFS as the file system, and choose “Erase” – WARNING: ALL DATA ON THE MAC WILL BE PERMANENTLY ERASED.

In Disk Utility, select “Macintosh HD” (or whatever the name of the drive to erase and clean install Big Sur onto is), then click the “Erase” button from the toolbar.

From the macOS Recovery / Utilities screen, choose “Disk Utility” from the options.

Select the “Install MacOS Big Sur” USB drive as the boot disk.

Apple Silicon Mac: Immediately hold the POWER button until the boot selection screen appears.

Intel Mac: Immediately hold the OPTION key until the boot selection menu appears on screen.

Next, boot into Recovery Mode, which differs depending on if it’s an Intel Mac or Apple Silicon Mac:.

Connect the MacOS Big Sur USB installer drive to a USB port on the Mac.

Be certain you have made a full backup fo the Mac.

Do not proceed if you do not want to remove all data from the Mac. Warning: This erases the entire Mac, setting it up as if it were new again.

How to Clean Install MacOS Big Sur (Reformat, Erase, & Factory Reset) An understanding that a clean install erases all data and everything else on the Mac – nothing will remain on the computerĪssuming you’ve met those prerequisites, and you understand what you’re about to do and why you’re doing it, here’s how you can clean install macOS Big Sur on compatible Intel Mac or Apple Silicon Mac.Active internet connection (required by macOS Big Sur for setup).Full Time Machine backup of all Mac data, or complete data backup using your method of choice.MacOS Big Sur boot installer drive that has already been created and ready to use.Mac compatible with macOS Big Sur so that it can run macOS 11.x.Failure to have sufficient backups will result in permanent data loss.Ĭlean installing MacOS Big Sur 11 requires the following: Because it erases the entire hard disk and all data on the Mac, it will cause complete data loss intentionally, so without sufficient backups theīefore proceeding, be certain you have a full backup of the Mac, and any or all important data. A clean install is generally for advanced Mac users only, and is otherwise not recommended unless you’re giving away a Mac or transferring ownership, and have fully backed up your data.

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