Download OS X installer from App Store
Follow these steps to download the version of OS X that you want to install .
1. from the Apple menu, choose App Store.
2. Hold down the Option key and click on the "Purchased Items " tab. You should be able to see the version of OS X you purchased previously . If you don't see your purchased item, sign in to the APP Store using the ID you used to install OS x.
3. Tap the Install button next to the version of OS X you want to download.
The Mac App Store typically displays OS X as "installed" in the "Purchased Items" Panel . this will prevent you from downloading again when your Mac has the same version of OS X installed. When you press and hold the Option key while clicking the Purchased tab , the button to the right of the item you want to download should become "installed ." If this button is not changed, use Spotlight to search for "install OS X" on your computer. It is possible that you already have a copy of the same OS X installer in your Applications folder or on the connected drive .
installing the OS X system using the U-disk
1, prepare a USB flash drive or removable hard disk that is not less than 8 g.
2. Open Launchpad ( the rocket icon on the Dock bar) or press F4 on the keyboard to go to the app page and Select the folder " other"
3, find the Disk utility , select the connected USB flash drive or removable hard disk , click Erase , format select OS X extension (journaled ), name change to myvolume, click to grind off
4, Download the latest system from the APP store, click the search box in the top right corner to search OS X, search for the first result OS X El Capitan download . Wait for the download to complete.
5. Open Launchpad (the rocket icon on the dock bar ) or press F4 on the keyboard to go to the app page , select "Other" in the folder and find "terminal "
6, copy the following code to the terminal :
Sudo/applications/install\ os\ x\ el\ capitan.app/contents/resources/createinstallmedia--volume/volumes/myvolume-- Applicationpath/applications/install\ os\ x\ el\ Capitan.app
7, enter, see hint Password:
8, enter the power on the login password , press ENTER (enter the password will not have any display, directly after the password return)
If there is no power-on password please go to ' System Preferences '-' users and Groups ', first click on the lower left corner of the small lock directly click Unlock, Unlock and click on the right to change the password to set a user name password, the old password is not filled, enter the new password directly
9, Prompt if you wish to continue type (y) and then ress return:
Enter Y return ,
You'll see the percent display.
Wait for the prompt to be done ( about-60 minutes to wait)
10, turn off the computer , press and hold the keyboard option to boot, select the USB flash drive or the removable hard drive
Go to OS X utility
12, select Disk Utility -Select native hard disk -partition -name can be named Mac. The partition only needs to be divided into a single area, click Apply .
13. Close the disk utility, go to OS X utility , select the second option , follow the prompts to install the new OS X, and wait for the installation to complete
Installing the OS X system using the U-disk