unknown sources, it's unable to turn on z5 dual

[mdossary]

Im unable to turn on the unkown source on my Z5

im the main user 

[_alexdon_]

Check under device administrators if there isn't an app that has been granted access to change your device settings.

[Bugmenotsony]

Go to --> Settings-->Security--->Device Administrators---> Disable step for step to find the culprit.

[lily5]

I can't unable to open the unknown sources