Logons failed after Mac upgrade Yosemite

After the Mac is upgraded to Yosemite, you cannot log on to the system. Today, we are busy preparing to play with the latest Apple system 10.10, code: Yosemite. I applied for the beta test qualification on the official website, and downloaded the Yosemite beta one night in the app store. The upgrade and installation process was smooth, but he was unable to log on after I restarted. He had been switching from the login page to the system for a long time. At that time, I had no backups of the Information. Fortunately, there was a powerful Google, and finally found a solution, which was a false surprise. This login problem is commonly reported on the Internet due to problems caused by third-party input methods or cleaning software such as cCleaner. I just installed these two software, after the upgrade, I used cCleaner to clear the system garbage once (some important files may have been cleared ). After an hour on the internet, I finally got a solution. Thanks to my friend jackatcl from macbookpro, I have posted the solution here, hope to help those who have upgraded the system.
The solution is as follows: 1. Press the power key to force shutdown, restart, and press command + S to enter the single-user mode after hearing the Startup sound. 2. Enter the command to mount the disk to write

 
Mount-UW/
 

3. Enter the following command to delete the file

 
Rm/var/DB/. applesetupdone
 

4. Enter the command to restart

Reboot
 

5. After the system is restarted, the wizard for creating a new user is displayed. You can simply configure it. Because only a temporary user needs to be created, I have created a user named test. 6. Use the test user to enter the system, download the DMG installation package for sogou Pinyin input method, open DMG, and uninstall the sogou input method. 7. unmount the account and log out of the account. enter your account and delete the user test.

Logons failed after Mac upgrade Yosemite