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Looking to reformat or erase your M1 Mac?

L

Lumpydog

macrumors 6502
Original poster
Aug 3, 2007
373
108
I've seen a number of posts where people have had challenges on their M1 Mac when reinstalling the OS from scratch or reformatting and reinstalling the OS or erasing their M1 Mac to return it. As of Big Sur 11.0.1 - doing this the traditional way, using the Recovery Tools causes issues (Using Disk Utility to erase or reformat the hard drive and then reinstall the OS).

I found a simple but obscure method/option that works and leaves you with a clean install of the baseline/clean OS and no bloatware (iMovie, Garage Band, Pages, etc - you can install them later if you want).

With Mac OS 11.0.1 here are the steps I used to successfully Erase my M1 Mac and reinstall the baseline OS:

1: Shut down your M1 Mac
2: Press and hold the power button down to enter recovery mode
3: Click the "Options" Gear-cog icon and then press the "Continue" button that appears below it
4: On the next screen, STOP. Look to the upper left corner - to the right the Apple Logo in the menu bar, select "Recovery Assistant" (it is the only menu item)
5: In that drop down menu, select "Erase Mac..."
6: Follow the on-screen steps from there

Note - you will need wifi access. From what I can tell, using this process completely reformats the Mac hard drive to a single partition, downloads a fresh copy of Big Sur, creates a new recovery partition and a new OS partition with an OS only install (no Garage Band, iMovie, Pages, Keynote, etc - which you can install later). The process took about an Hour and ten minutes.

After the OS re-installation is complete, your Mac will restart to a setup assistant. If you're selling, trading in, or giving away your Mac, press Command-Q to quit the assistant without completing setup. Then click Shut Down. When the new owner starts up the Mac, they can use their own information to complete setup. Otherwise, follow setup assistant and Welcome to your clean Mac with no bloatware.

The obscure "Erase Mac..." selection in the Recovery Assistant drop down menu is the easy button to wipe/reset your Mac's OS.
 
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1

1240766

Cancelled
Nov 2, 2020
264
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Lumpydog said:
I've seen a number of posts where people have had challenges on their M1 Mac when reinstalling the OS from scratch or reformatting and reinstalling the OS or erasing their M1 Mac to return it. As of Big Sur 11.0.1 - doing this the traditional way, using the Recovery Tools causes issues (Using Disk Utility to erase or reformat the hard drive and then reinstall the OS).

I found a simple but obscure method/option that works and leaves you with a clean install of the baseline/clean OS and no bloatware (iMovie, Garage Band, Pages, etc - you can install them later if you want).

With Mac OS 11.0.1 here are the steps I used to successfully Erase my M1 Mac and reinstall the baseline OS:

1: Shut down your M1 Mac
2: Press and hold the power button down to enter recovery mode
3: Click the "Options" Gear-cog icon and then press the "Continue" button that appears below it
4: On the next screen, STOP. Look to the upper left corner - to the right the Apple Logo in the menu bar, select "Recovery Assistant" (it is the only menu item)
5: In that drop down menu, select "Erase Mac..."
6: Follow the on-screen steps from there

Note - you will need wifi access. From what I can tell, using this process completely reformats the Mac hard drive to a single partition, downloads a fresh copy of Big Sur, creates a new recovery partition and a new OS partition with an OS only install (no Garage Band, iMovie, Pages, Keynote, etc - which you can install later). The process took about an Hour and ten minutes.

After the OS re-installation is complete, your Mac will restart to a setup assistant. If you're selling, trading in, or giving away your Mac, press Command-Q to quit the assistant without completing setup. Then click Shut Down. When the new owner starts up the Mac, they can use their own information to complete setup. Otherwise, follow setup assistant and Welcome to your clean Mac with no bloatware.

The obscure "Erase Mac..." selection in the Recovery Assistant drop down menu is the easy button to wipe/reset your Mac's OS.
Click to expand...
I have been posting this on a few threads....easy as you describe.
 
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A

Alicia1

macrumors 6502a
Nov 13, 2009
568
545
Gold Coast, Australia
Thanks for posting this, wish I had of done these steps last night when I erased the air I am not keeping to return to apple. Oh well, apple can sort it out when they get it.

Scared to try it though on the air I am keeping :(
 
L

Lumpydog

macrumors 6502
Original poster
Aug 3, 2007
373
108
Alicia1 said:
Thanks for posting this, wish I had of done these steps last night when I erased the air I am not keeping to return to apple. Oh well, apple can sort it out when they get it.

Scared to try it though on the air I am keeping :(
Click to expand...

It will work on the one you're not keeping. I learned of this option from a developer's forum when I was working to undo the badness I ran into reformatting/erasing my M1 Air the way we are all used to (and the way that Apple provides/documents).

Those of you that are running into formatting issues doing it the way we're all used to - these steps get you out of jail free...
 
A

Alicia1

macrumors 6502a
Nov 13, 2009
568
545
Gold Coast, Australia
Lumpydog said:
It will work on the one you're not keeping. I learned of this option from a developer's forum when I was working to undo the badness I ran into reformatting/erasing my M1 Air the way we are all used to (and the way that Apple provides/documents).

Those of you that are running into formatting issues doing it the way we're all used to - these steps get you out of jail free...
Click to expand...
I also tried something similar to this following apples instructions however it said there was no user account (this was after I erased it the "used to be" normal way.
 
L

Lumpydog

macrumors 6502
Original poster
Aug 3, 2007
373
108
Zazoh said:
This works great. It leaves the Drive titled "Untitled" which can be changed when it is up and running by going to /Volumes in Finder.
Click to expand...
Zazoh - good call. I noticed this and I was actually able to change this back to "Macintosh HD" as I walked through the process I described in the original post - I don't remember at what point, but it was editable.
 
L

Lumpydog

macrumors 6502
Original poster
Aug 3, 2007
373
108
Alicia1 said:
I also tried something similar to this following apples instructions however it said there was no user account (this was after I erased it the "used to be" normal way.
Click to expand...
Yep - I had that same error message. This process/workflow bailed me out.
 
Bending Pixels

Bending Pixels

macrumors 65816
Jul 22, 2010
1,307
365
I posted this last week on this same forum (and sent the info to MacRumors - no response from them)
 
MrMacintoshBlog

MrMacintoshBlog

macrumors 6502
Sep 21, 2009
458
311
Chicago, IL
If anyone is looking for a video walkthrough.




I also show you what to do if you don’t see the user login screen where you would normally select the Erase Disk option. You need to go into terminal and run resetpassword.
 
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L

Lumpydog

macrumors 6502
Original poster
Aug 3, 2007
373
108
ClassicII said:
If anyone is looking for a video walkthrough.




I also show you what to do if you don’t see the user login screen where you would normally select the Erase Disk option. You need to go into terminal and run resetpassword.
Click to expand...
Nope - this is a completely different solution/walk through. I would NOT recommend following the steps outlined in this video as it is unnecessarily difficult.
 
Last edited:
MrMacintoshBlog

MrMacintoshBlog

macrumors 6502
Sep 21, 2009
458
311
Chicago, IL
Lumpydog said:
Nope - this is a completely different solution/walk through. I would NOT recommend following the steps outlined in this video as it is unnecessarily difficult.
Click to expand...
You made a great thread with nice instructions. The video is for users who did not enable FileVault 2 as they will not get the menu you are talking about in your instructions. In this case the the user would have to open terminal and run resetpassword to get the Recovery Assistant menu to show up.
 
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K

kave

macrumors 6502a
Oct 31, 2012
567
308
Sweden
What I find so strange is that even though I boot from a USB installer I can't erase the internal drive from the install/recovery menus with diskutil.
 
D

dialekt

macrumors regular
Jun 3, 2014
100
11
ClassicII said:
If anyone is looking for a video walkthrough.




I also show you what to do if you don’t see the user login screen where you would normally select the Erase Disk option. You need to go into terminal and run resetpassword.
Click to expand...

I haven’t heard about anyone talking about restoring from a clone/backup? (carbon copy cloner) - would I go through setup & use migration utility somehow after bootable usb? it’s confusing to know whether to follow the video OR the original posters instructions. Also find it strange to be able to change volume name?
 
macnmac

macnmac

macrumors 6502a
Jun 18, 2017
778
609
Apple Park
just went to restore my air and got the error message and now i cant even go back and need to make a bootable installer to get it working again...
 
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