I could not recover macOS in recovery. Had no old recovery and some how deleted Macintosh HD how do I get computer to work

Helplessmacuser1185 Said:

"I was trying to pair my new AirPods to my Mac air 2015 and had macOS serria I try to recover it but kept get -405 seconds message so I did disk utility and some how delete machintosh hd. Now my computer does nothing but disk password. Have no money to take to shop. Is there any way to reset full computer. I am okay with losing all the files in the computer"

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Getting the macOS Back:

Two Major Thoughts:

A. Restore form a Backup:

Did you create a backup of your Mac prior to upgrading? Is so, then restore from the backup. If not, then take this as a learning experience, knowing to always backup your Mac, prior making any major changes to your Mac (i.e. upgrading your MacOS).

or...

B. Reinstall the macOS Anew:

The ultimate workaround would be through a new install.

Reinstalling the macOS Anew:

Try This:

1. First, Backup your Mac, then

2. Then, install your macOS Big Sur anew.

3. Finally, migrate it over from the Backup created in step 1

In Depth:

1. Back up your Mac:

Start by Creating a Time Machine Backupof my Mac. That way I could be assured that Incan recover my Mac, should I need the App back or if anything goes wrong due to the removal. So, Create a Time Machine backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong with the reinstall.

2. Use a USB Bootable Installer:

Create a USB Bootable Installer for Big Sur. Delete the hard drive's partition. Then, install this macOS with. Go Here: How to Create a Bootable Installer for macOS - Apple Support.

3. Migrate and Reinstall Data and Apps:

Next migrate it over from the Time Machine Backup you created in step 1 to this new install.