Update: Thanks to a helpful comment from Alain Roy, the answer is here – Sleep unattended idle timeout
There is a Group Policy setting called “Specify the unattended sleep timeout” located here;
Computer Configuration – Administrative Templates – System – Power Management – Sleep Settings
The description given for the policy is;
This policy setting allows you to specify the period of inactivity before Windows transitions to sleep automatically when a user is not present at the computer.
If you enable this policy setting, you must provide a value, in seconds, indicating how much idle time should elapse before Windows automatically transitions to sleep when left unattended. If you specify 0 seconds, Windows does not automatically transition to sleep.
If you disable or do not configure this policy setting, users control this setting.
If the user has configured a slide show to run on the lock screen when the machine is locked, this can prevent the sleep transition from occurring. The “Prevent enabling lock screen slide show” policy setting can be used to disable the slide show feature.
What I want to know is how on earth the system determines when it’s unattended. What if you’re watching a full screen video, is that unattended? What if you’re just running an Excel calculation, is that unattended?
I can find very little information, none in fact, on the Internet on how this is determined, but if anyone knows, please share.