MacBook not asking for password after sleep

Solution 1:

Not sure if you set it in the correct place, but the setting should be at:

1. Choose Apple menu > System Preferences, click Security & Privacy, then click General.
2. Select “Require password… after sleep or screen saver begins.”
3. Click the pop-up menu and choose the time that passes before a password is required.

Source: OS X Yosemite: Require a password after waking your Mac

Solution 2:

I found that I was able to fix this problem on 10.12.6 using the following steps:

1. Set "Require password" to "immediately".
2. Lock the screen or put the machine to sleep.
3. Set "Require password" back to your preferred time delay (1 minute).

Solution 3:

Steps I did to make laptop lock as intended.

1. Require Password > Immediately
2. Apply and close that setting window, quit "Settings"
3. Unplug USB device before initiating Lock
4. In my case it was a USB Headset that was preventing Lock
5. Enjoy computer being locked.

Solution 4:

OS X High Sierra

1.  menu > System Prefrences > Users & Groups
2. Click Login options at the bottom of the sidebar
3. Settings might be disabled. Unlock them (by clicking the lock at the bottom) to make changes.
4. After unlocking, set Automatic login to "Off"