Need some privacy

[Jayesh Madoori]

I am using Sony Xperia m5 Dual E5663 android version 6.0.
I m trying to put pattern lock instead of swipe to unlock but every time I click on screen lock option in setting it crush, saying unfortunately setting has stopped working. Please help me to add some privacy to my device. Please have a look at this video https://youtu.be/xP8YGqJd7UQ

And help me.
Thnx in advance

 

[SpookDroid]

Have you tried clearing cache from the Settings 'app' in the Application Manager? What about trying the setting in Safe Mode (to make sure no other app is conflicting with it)? If you have a Device Manager that can control lockscreen settings (like Corporate EMail accounts, etc.) that might also be causing a conflict.