Why is the "None" option now missing from the "Lock Screen" setting on my ASUS Zenfone 2?

[AC Question]

Why is the "None" option now missing from the "Lock Screen" setting on my ASUS Zenfone 2?

My "Lock Screen" setting originally showed four options - "Swipe," "Pattern," "PIN," and "Password." After a factory reset, it added a fifth option - "None." Now, it again lists only the four original options with the "None" option missing. How do I correct this? Thank you very much.

 

[B. Diddy]

Re: Why is the "None" option now missing from the "Lock Screen" setting on my ASUS Zenfone 2?

Welcome to Android Central! Try going to Settings>Security>Clear Credentials. Now see if "None" is back.

 

[Kevin Yun]

Re: Why is the "None" option now missing from the "Lock Screen" setting on my ASUS Zenfone 2?

there is no" Clear Credentials" in security. but once you cleared all cache by Clean Master. the "None" return.