Mac mini Late 2014 how to factory reset
Mac mini Late 2014 how to factory reset
Mac mini, OS X 10.10
Question marked as
This guide covers how you wipe everything and reinstall:
What to do before you sell, give away, or trade in your Mac - Apple Support
The most important part is part 8 erase and reinstall. but I would advice to follow the guide.
-------------------------------
Erase your Mac and reinstall macOS
After you erase your Mac and reinstall macOS, your Mac restarts to a setup assistant. Press Command-Q to shut down instead of continuing setup.
-------------------------------