Enabling Dynamic Lock

Once you connect your phone via Bluetooth to Windows 10 build 15031, you need to use the steps below to enable Dynamic Lock:

  1. Open Settings.
  2. Click on Accounts.
  3. Click on Sign-in options.

  4. Under Dynamic Lock, check the Allow Windows to detect when you're away and automatically lock the device option.

After completing the steps, you should be able to walk with your phone away from your computer, and after 30 seconds your computer should lock automatically. However, remember that this security feature is meant to lock your PC when coming back, you'll need to enter your password to unlock it.

Dynamic Lock still under development and may or may not work for everyone. If it's not working after connecting your phone, you can try restarting your computer and testing again.

As a last resort, if you still can't connect your phone using Bluetooth, you can alternatively go to Settings > Update & security > Recovery, and use the option available to go back to the previous version of Windows 10.