I have a MacBook Air model A1466 and it’s been sitting idle for about a year. I forgot my password and not sure of the login information. What do I do to get this back to the factory setting, so I can start all over?

There are a few ways to try & reset various mac user and Admin account passwords.

..Details about Passwords and then again more Passwords..

Important: If you’ve forgotten or need assistance with

a login password, the following topics may help:

• If you forget your login password on Mac
• Reset your Mac login password
• Learn how passwords are used on Mac
• Change your password, user picture, or automatic login items on Mac
• Ways to remember passwords on Mac

from: • Change Users & Groups User Preferences on Mac - Apple Support

Lesser Admin passwords (without FileVault) are easier to figure.

• Reset your Mac login password - Apple Support

https://support.apple.com/guide/mac-help/reset-your-mac-login-password-mh35902/mac

With 'four different ways' to try and reset the lost Admin password, a

few might help access the Mac in order to reset those hardest ones.

[Given finality of FileVault, if that's what you have; try shooting in dark.]

• 4 Ways to Reset a Lost Admin Password on Mac OS X - wikiHow

https://www.wikihow.com/Reset-a-Lost-Admin-Password-on-Mac-OS-X

Was there a FileVault created for this Mac's hard drive?

If so, certain protections make this almost inaccessible.

This link also includes details on how to try/& change it.

• User FileVault to encrypt the startup disk on your Mac - Apple Support

https://support.apple.com/en-us/HT204837

In the above page, how to "Turn off FileVault" is detailed.

As bystander, hard to suggest an actual cure of anything.

• What you can do if you forget your password on a FileVault-protected Mac | Macworld

https://www.macworld.com/article/3175691/what-you-can-do-if-you-forget-your-password-on-a-filevault-protected-mac.html

• Forgot your Mac password? | 3 ways to unlock startup disks encrypted with FileVault - TechRepublic

https://www.techrepublic.com/article/forgot-your-mac-password-3-ways-to-unlock-startup-disks-encrypted-with-filevault/

[Some of these resets require an official Apple technician +

they'd want proof of purchase to disable/unlock the drive.]

Generally these basic ones try to 'hit a nail' on the head, 1 of 3 tries.

• Three Ways to Reset a Lost Admin Password (in High Sierra) - TidBITS (2018)

https://tidbits.com/2018/07/05/three-ways-to-reset-a-lost-admin-password-in-high-sierra/

• Change or reset the password of a macOS user account - Apple Support

https://support.apple.com/en-us/HT202860

• Five Ways to Reset a Lost Administrator Password | TidBITS (2014)

https://tidbits.com/2014/01/17/five-ways-to-reset-a-lost-administrator-password/

There had been a way (details forgotten) to reset a password via

iCloud.com login? maybe. ~ Somewhere else to try duckduckgo.

• Mac Help - { Table of Contents } - Apple Support

https://support.apple.com/guide/mac-help/toc/10.13