How to force stop/block/blacklist UC News and 9apps from installing in my android phone for whole life I am annoyed of the unwanted apps UC News, 9Apps and some other apps from automatically installing on my android phone. I have disabled  install unknown source applications, but everytime I restart my phone this is automatically enabled and then my internet is automatically switched on and then nearly 10 to 20 apps are automatically installed in my phone.

I have factory reset my phone many times but even after factory reset same thing occurs and all apps are installed. I suspect this is because of UC browser being an inbuilt app. In UC browser their shows some related apps in which UC News and 9apps is also showm. These two apps are the first to be installed whenever I restart my phone. 

My phone is Xolo Era 4g. Plz tell me:  


How to block/blacklist xyz app in android permanatly so that it never installs again in whole life of phone.  
How to not let andriod switch unknown sources option on when phone is restarted.


I do not want to root my phone to forego the gaurantee. So plz tell any way without rooting the phone, even if it requires downgrading android version or using any other possible OS.  
If there is no way then plz tell the method with rooting the phone.  



Thanx.
One way to avoid all such issues is by rooting your phone.
That gives you plenty of control on it (it becomes essentially a Linux box), and you can install one of many possible flavors of Operating System (custom ROM).

Judging from this Google search, rooting your model is something already worked out.

Nevertheless, you have to be careful, since it may "brick" your phone, i.e., make it useless. For many phones, there are very detailed instructions available on how to do that.

PS1: A few links in this Google search (e.g.) report users which did not get rid of auto-installed apps, even after rooting. Whatever these users did, it has to be taken with a grain of salt, though.

PS2: UC Browser has been under some criticism for its lack of privacy/security and invasivity.