Disk Lost - can not reinstall the OS

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Level 1

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Disk Lost - can not reinstall the OS

Dear All,

My MacBook Air mid-2012 started being hot, noisy and slow. After time spend with Activity Monitor with no real clue on the next steps, I've started looking for solution including reimaging. Checked the web and found couple of shortcuts like Command+R and D pressed during the boot.

I have managed to play around with Diagnostic tools, running checks on disk. Then I got mislead by two disks coexisting Mac HD and Mac HD (data) which led me to further steps. The one I went too far was related to deleting partition. I did it as the OS reinstallation found too little space on the disk.

Now, my Mac does not have a OS (the folder with question mark appears). I have tried several times to recover from the Internet that led a step forth - OS Lion is now offered to be installed, however still no disk is found.

Can you please advise on how do I reinstall my Mac again to any state of operation?

Happy to hear from you. M

MacBook Air 13″, macOS 10.15

Posted on Jun 28, 2022 7:17 AM

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Answer 1

Top-ranking reply

Tesserax

Level 10

151,977 points

Jun 28, 2022 11:43 AM in response to MarioFleish

Since your MacBook Air was running macOS Catalina, most likely, its internal SSD was formatted in APFS. As such Catalina is installed in a two-volume group: Macintosh HD & Macintosh HD - Data (by default.) Both of those reside in a single Container (what used to be called a partition.) When you deleted that partition, you effectively removed the operating system.

At this point, in an attempt to reinstall macOS, you will need to first fully erase the internal drive, and then, install a "fresh" copy of macOS. Your 2012 MBA can run up to Catalina.

To erase the system drive, boot up your notebook in Recovery Mode, and then, follow the directions in this article:

Use Disk Utility to erase an Intel-based Mac - Apple Support

Once completed, then follow these directions:

How to reinstall macOS - Apple Support

Ref: About macOS Recovery on Intel-based Mac computers - Apple Support

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Answer 2

HWTech

Level 9

60,284 points

Jun 29, 2022 12:56 PM in response to MarioFleish

If you are booting the Lion installer, then you will need to partition and format the whole physical drive using the instructions in this article since macOS 10.13+ utilize a new drive layout & file system which older versions of macOS do not understand:

https://www.owcdigital.com/assets/support/support-formatting-and-migration/Mac_Formatting_6-10.pdf

If you have access to another compatible Mac from 2008 to 2019 (maybe even some from early 2020) in order to create a bootable macOS USB installer using the instructions from this Apple article:

How to create a bootable installer for macOS - Apple Support

To create a bootable macOS 10.11 USB installer requires a Mac from 2008 to 2011, while creating a bootable macOS 10.15 USB installer requires a Mac from 2012 to 2019 (maybe even early 2020). You can use the information in this article to see which versions of macOS are compatible with various Apple hardware:

https://eshop.macsales.com/guides/Mac_OS_X_Compatibility

FYI, here is some information regarding the new drive layout beginning with macOS 10.15 Catalina as @Tesserax already mentioned:

About the read-only system volume in macOS Catalina - Apple Support

If you have any Macs running macOS 11.x +, then you may also be interested in the further changes Apple has implemented regarding a signed & sealed system volume:

Signed system volume security in iOS, iPadOS, and macOS - Apple Support

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Disk Lost - can not reinstall the OS

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