Back up your data (Time Machine or another backup method)
Sign out of iCloud: Apple menu → System Settings → Apple ID → Overview → Sign Out
Sign out of other services: Apple menu → System Settings → [your name] → Media & Purchases → Sign Out; also sign out of iMessage if prompted
Turn off Find My: Apple menu → System Settings → Apple ID → Find My → Find My Mac → Turn off
Shut down your Mac
Start Recovery mode:
Apple silicon (M1/M2/M3): press and hold the power button until “Loading startup options,” then select Options → Continue
Intel: shut down, then press power and immediately hold Command (⌘) + R until you see the Apple logo or a spinning globe
In Recovery, open Disk Utility
Erase the startup disk:
Select your startup disk (typically “Macintosh HD”)
Click Erase
Set Format:
If prompted, choose APFS
Set Scheme:
Use GUID Partition Map
Click Erase
Quit Disk Utility
Reinstall macOS:
Select “Reinstall macOS”
Follow the on-screen prompts to install the latest compatible macOS
After installation, complete setup:
Choose region and keyboard
If you’re selling/giving away the Mac, stop at the setup screen and do not sign in
If keeping the Mac, complete setup and restore data from backup