Mac OS is the best desktop operating system today, but even a better system has a new version released one day, or it is messy when you try various settings by geeks, in this case, we need to update or reinstall the system.
System update
When a new version of Mac OS is released, it will be automatically notified in the App Store, as long as you enter the App Store and click Update, it is quite easy.
Reinstall the system
Mac OS comes with a recovery system. You only need to press and hold the "option" Key (that is, the third key ALT in the lower left corner of the keyboard) and the "R" key at the same time, and then press and hold the system on, after the familiar Apple logo appears, release the button to go to the recovery system. You can select to reinstall the system to automatically download the latest Mac OS from the Internet for installation.
The following are related operation videos:
Original article, reprinted Please note:Reposted from http://www.mr-wu.cn/Wu chuanbin's blog
Link:How to update and reinstall Mac OS http://www.mr-wu.cn/how-to-upgrade-or-reinstall-mac-os-x/ with Mac OS skills
[Video] how to update and reinstall Mac OS