Description: This article will show you how to reinstall macOS. This works for macOS 10.7 and later versions.

1. Turn the Mac on and immediately press down the Command + R keys. The keys must be pressed before the grey screen appears. Hold them down until the Apple logo displays on the screen. When finished booting up, macOS Utilities will open.
   
2. If you need to wipe the system clean, select Disk Utility. Select Macintosh HD on the left and then Erase at the top. A window will display prompting you to select a format and name the drive. With macOS 10.12 or earlier, select Mac OS Extended Journaled. With macOS 10.13 or later, select APFS.
   
   The drive will be erased and all data on it will be lost, this action cannot be undone.
   
   
   
   If you need to keep your data you can skip this step and go to the next step.


3. Close the Disk Utility window to return to macOS Utilities. Select the wifi icon at the top of the screen and make sure you are connected to your internet then choose Reinstall macOS.
   
4. Follow the prompts on the screen to reinstall macOS. Make sure to select the same drive that you erased before if it asks what drive you want to install to. Once the installation begins the process will take some time to complete. Keep your computer plugged in to ensure it does not shut down and interrupt the install.
   
5. Once the installation is finished your system will restart.