I suggest you install recovery first (even if you have it) and make a system backup (Baidu: recovery system backup)! Then enter the system to see which software is neither Samsung's nor Google's (such as Mi Chat, Youni SMS, Public Comment, Stock, Sohu News, Anzhi Market, Extreme Travel, if there is a QQ mobile phone housekeeper, the mobile phones starting with 360 and TT have been deleted). Don't delete it if you are not clear, and then delete it when you become a master. If you delete some programs, it will directly lead to the system crash, such as the telephone program phone. Paper is used to determine the software to be deleted. After the execution, if you feel normal for a few days, then back up the system. If it is not normal, use recovery to restore the system (Baidu: restore system recovery).