I disabled the lock in the "Brightness & Lock" but I still get the lock screen when is resumes/wake from suspend. Although the option "Require my password when waking from suspend" is unchecked
There is two steps involved into completely disabling the lock screen in Unity.
go to search , type Unity, in the options displayed find and double click on option "Unity Tweak Tool", a windows opens inside that you will find main options like
under "system" there are 3 sub option "Desktop" , "Security", "Scrolling"
I am adding this solution just in case if unable to find the option.
Thanks for the all previous post's. very helpful and informative.