You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

When it’s time for me to erase the volume that my macOS is installed on?

I am following the directions according to this document:


https://support.apple.com/guide/mac-help/erase-and-reinstall-macos-mh27903/10.15/mac/10.15


When it’s time for me to erase the volume that my macOS is installed on, I see two volumes. They are both identical except for the amount of used space and the amount of other volumes. The names are identical except one says ” - Data” at the end. The amount of space available are the same. Which of these volumes should I erase?


[Re-Titled by Moderator]

Mac mini, macOS 10.15

Posted on Nov 12, 2021 5:58 PM

Reply
Question marked as Top-ranking reply

Posted on Nov 13, 2021 2:33 AM

The Follow Method will WIPE ALL DATA including the Recovery Volume.


Proceed with Caution.


To perform this action will require booting from a Bootable Installer


This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Big Sur would have to be done on a computer that Qualifies to run Big Sur.


Once that is done read on for preparing the Destination computer  >>


Only works on Intel Based Apple Computers.


Extra Special Notation regarding the Touch ID equipped Apple Computer. About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting 


1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.


2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive. 


3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives. 


4 - Choose the Upper Most Drive ( not the volumes indented and list below ).


5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map. 


6 - Once that is done >> backup out of Disk Utilities and choose install macOS. 


7 - Follow the prompts and it may automatically reboot several time. 


8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.

Similar questions

2 replies
Question marked as Top-ranking reply

Nov 13, 2021 2:33 AM in response to madirmur59

The Follow Method will WIPE ALL DATA including the Recovery Volume.


Proceed with Caution.


To perform this action will require booting from a Bootable Installer


This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Big Sur would have to be done on a computer that Qualifies to run Big Sur.


Once that is done read on for preparing the Destination computer  >>


Only works on Intel Based Apple Computers.


Extra Special Notation regarding the Touch ID equipped Apple Computer. About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting 


1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.


2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive. 


3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives. 


4 - Choose the Upper Most Drive ( not the volumes indented and list below ).


5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map. 


6 - Once that is done >> backup out of Disk Utilities and choose install macOS. 


7 - Follow the prompts and it may automatically reboot several time. 


8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.

Nov 12, 2021 6:39 PM in response to madirmur59

There is a step missing from that Apple document. You want to erase the entire drive, not just the startup volume.

2A - After you launch Disk Utility you should then click the View menu and select Show All Devices.

This allows you to actually select the startup device that you will now want to erase and partition. Select the topmost device, not an indented volume, click erase and then apply name Macintosh HD, apple the APFS format and use the GUID partition scheme.

When it’s time for me to erase the volume that my macOS is installed on?

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.