Then select Overview in the side panel and click Sign Out.

Choose iCloud in the side panel and Turn off Find My Mac.Choose Apple menu > System Preferences, then click Apple ID.

When prompted, enter your Apple ID and password. Open iTunes. From the menu bar at the top of your computer screen or at the top of the iTunes window, choose Account > Authorizations > Deauthorize This Computer. If your computer has not been updated to Catalina, you will need to deauthorize your computer from the iTunes app.

Resetting a Mac to factory settings deletes all the data stored on that device, you can make a backup of the data using Time Machine software Apple provides - Here's how to back up using Time Machine. You should back up your computer, disable some features and services, and then go on booting to Recovery Mode and using Disk Utility to erase (format) a hard disk and reinstalling macOS. Things you can do before you erase a Macbookīefore you erase your Mac, make sure your Mac is currently connected to the internet and plug in the power adapter, so there's no danger of running out of battery power.

Open mac os x utilities