If you are trying to sell an ancient Mac that has a mechanical hard drive instead of a solid-state drive, then choose Mac OS Extended (Journaled) for Format. Why not go with the tried-and-true Macintosh HD? Name: Choose a name for the fresh, new volume.You simply press and hold the power button until you see the startup options window, then click Options and Continue to get to the utilities window.) On an M1-based Mac, booting into Recovery Mode is slightly different. You can release the keys once you see the Apple logo. To enter Recovery Mode on an old Intel-based Mac, restart it and immediately press and hold Command-R. You need to put your MacBook into Recovery Mode in order to erase all of your data and reinstall

That's it! Your Mac's NVRAM has been reset. You can release the keys after 20 seconds or so. To do so, shut down your Mac, then turn it on and immediately press and hold four keys together: Option, Command, P, and R. Sometimes these files can get corrupted, so give your Mac's next owner a fresh start by resetting the NVRAM. NVRAM is memory to which your Mac saves settings that it needs before loading MacOS: things like screen resolution, time zone, volume level and startup-disk selection.

How to clean out macbook