A. First, download macOS
1. appStore search
For the first time when the next will prompt the machine has been installed macOS update in the update system, click Continue to continue downloading
2. After the download is complete the file in the Finder
II. Prepare a greater than 8G U-disk renamed Sierra, U disk and the backup data
1. Open the "Applications → Utilities → Disk Utility" U disk "erase" (format) into a "Mac OS X Extended (Case-sensitive, Journaled)" format, GUID partition map, and U disk named "Sierra." (Note: This letter will correspond with the name behind the command, if you change the name of this letter, we must ensure that in the back of the command name should be the same.)
Note: Be sure to select Show all devices, click General USB
2. Open the "Applications → Utilities → Terminal", copy and paste the following section of this command:
If you want to make High Sierra, copy this command:
sudo / Applications / the Install \ macOS \ High \ Sierra.app/Contents / Resources / createinstallmedia --volume / Volumes / Sierra --applicationpath / Applications / the Install \ macOS \ High \ Sierra.app --nointeraction
* Please note the red "Sierra" to correspond to your U disk named
3. Enter and execute the command, then you will be prompted to enter the administrator password, will start the production process:
After completing the prompt Done
III. To make good use of U disk can reinstall the system, remember to back up system data
Then Command + option + R + P into the