Erase and reset MAC

[Genegene]

Just installed"Erase and reset your MAC". It was going great with only 6 minutes left in the erase mode.
I then pulled out the power supply thinking it would run on battery. WRONG
Everything stopped and all I get now is a screen with a question mark in a box. Nothing changes that
Appreciate any ideas for completing the operation

 

[hg.wells]

You will likely have to do an Internet Recovery to reinstall the OS

• Option-Command-R: Start up from macOS Recovery over the internet. Use this key combination to reinstall macOS and upgrade to the latest version of macOS that’s compatible with your Mac.
• Option-Shift-Command-R: Start up from macOS Recovery over the internet. Use this key combination to reinstall the version of macOS that came with your Mac or the closest version that’s still available.

Use macOS Recovery on an Intel-based Mac

Learn how to use macOS Recovery on an Intel-based Mac.

support.apple.com

 

[Genegene]

You will likely have to do an Internet Recovery to reinstall the OS

• Option-Command-R: Start up from macOS Recovery over the internet. Use this key combination to reinstall macOS and upgrade to the latest version of macOS that’s compatible with your Mac.
• Option-Shift-Command-R: Start up from macOS Recovery over the internet. Use this key combination to reinstall the version of macOS that came with your Mac or the closest version that’s still available.

Use macOS Recovery on an Intel-based Mac

Learn how to use macOS Recovery on an Intel-based Mac.

support.apple.com

This worked very well.
I am happy to have found MacRumors and will follow in the future.
Thank you.

 

[NeetalS]

Guys, I have the same problem. I was installing Catalina and it stopped. I restarted the installation but now I can't see any Disk Volume other than macOS Base System in Disk Unitilies. It seems my HDD is not there.

I downloaded Catalina on my other MBAir but it will not allow me to make the bootable USB as MBAir is working on Big Sur.
any idea how to make Catalina bootable USB on Big Sur?