Fix Windows 10 Sign-in Problems
One issue I have come across on several Windows 10 installs is the incorrect handling of security when signing in after sleep. Despite the modern UI accounts control panel being set to 'Every Time' or 'Never' some machines will ignore the setting completely.
This happens because the power management classic control panel has a separate setting for deciding what happens when your PC wakes from sleep and for some reason sometimes changes made in the modern UI control panel aren't pushed through to here.
So if your PC isn't doing what you want the fix is simple, even if the problem can be frustrating.
Open the settings control panel and type 'power' into the search box. The first result should be 'Power and Sleep settings' open it and scroll to the bottom to select 'Additional Power Settings' which will open a classic control panel window. On the left hand side select 'Require a password on wakeup' which will eventually get you to the screen above.
The option you need is halfway down the page. If it is greyed out, as in the picture, you need to click the 'Change settings that are currently unavailable' link to make them selectable.
Fortunately it takes longer to read than to do and has worked everywhere I have tried it.