MacOS Sierra Update Upgrade Tutorial:
Because the Mac's downgrade method is relatively complex and time-consuming, so before you install the beta version, please complete this tutorial, and then decide whether to be a delicacy.
Prepare: Back up your Mac first or back up your computer, unless you have the data on the computer does not matter, otherwise make sure to back up, do not lazy. You can choose to copy important data to a mobile hard drive, but it is more recommended to use time Machine to make a full backup of your Mac.
1, upgrade MacOS Sierra and iOS10 beta version, you need to first login to the Apple beta version of the website, in the "Register your device" to choose MacOS;
2, the system will provide you with an Exchange code, click the "Exchange Code" button below will jump directly to the Mac app Store;
3, in the pop-up Mac App Store page click "Redeem", then the system will automatically download MacOS Beta version.
Note: At present, due to Apple reasons, the central MAS attempt to redeem will prompt "Redemption failure, the project is no longer available", the temporary solution is: Using the U.S. Apple ID, you can successfully redeem the download.
Degraded back to OS X El Capitan degraded Mac system is troublesome, after upgrading to the beta version, you can no longer use the system "recovery mode" directly back to the formal version of the system, but also not in the Mac App Store directly download the OS X installer to install, you can only reload the system. One of the most stable and efficient way is to reload via U disk. The specific steps are as follows:
1. Back up the important files on the Mac in the cloud or on the hard drive;
2. To prepare a U disk of 8 GB or more, in the process of making system installation disk will be formatted on U disk, please make sure there is no important data in U disk;
3. Insert a U disk into the Mac, turn on the disc tool, select U drive;
4. Choose "Erase" option, and then rename the U disk to untitled and wipe off;
5. Search the Mac App Store for "os x" download OS X El Capitan installation files;
6. After downloading completes installs the program to start automatically, at this time presses the COMMAND+Q key to close installs the program;
7. Open the terminal, enter the following code in the application, confirm by carriage return;
Sudo/applications/install\ os\ x\ El capitan.app/contents/resources/createinstallmedia--volume/volumes/untitled-- Applicationpath/applications/install\ os\ x\ El Capitan.app--nointeraction
8. Enter the administrator password, confirm by carriage return;
9. Wait for the command to complete and display the "done.", at this time the system Startup disk production completed;
10. Restart your Mac, hear the power-on start tone after the option key, select the disk in the selection of the interface USB disk to start, by return confirmation;
11. At this time the system will enter the OS X utility, first select "Disk Utility", ready to format the hard disk;
12. In the "Disk Utility" Select the built-in hard disk, click the "Erase" option to format the hard disk;
13. After the format is completed, exit the disk tool, select "Install OS x", install the system on your internal hard drive; "
14. According to the prompts to operate, waiting for installation to complete.
Once the installation is complete, you will enter the new OS X El Capitan System, complete Setup, enter the time machine application, and restore the previous backup from the mobile hard drive.