Hi, I'm John! I will help you with this.
The "Lock" button is actually a normal, built-in feature in Windows 10. But if something feels off about it, I’d be happy to take a closer look with you.
Could you share a screenshot of what you're seeing, just so I can make sure everything looks the way it should?
Also, when did you first notice it, was it after a recent update or any changes you made to your PC?
Click "Reply" below to let me know.
Regards,
John J.D.