Task scheduler - What is "Wait for idle for"?

You are right: that explanation is very hard to follow! I'll try to explain it a different way:-

In your screenshot you have a task that will trigger at a certain time. When this task triggers, it will only execute if the statement "the computer has been idle for 10 minutes" is true. The task will wait up to an hour for the statement to become true, and then it will give up.

If the computer has been idle for 10 minutes or more when the task is triggered, it will execute immediately. Otherwise it will wait.

If the computer becomes idle after, say, 15 minutes after the task triggered, the task will continue waiting. 25 minutes after the task triggered, the statement "the computer has been idle for 10 minutes" becomes true, so the task will execute.

If the computer doesn't become idle within 50 minutes of the task being triggered, the task will not execute. That's because the task will stop waiting after 60 minutes, so if the computer becomes idle more than 50 minutes after the task was triggered, the statement "the computer has been idle for 10 minutes" won't be true until after the specified 1 hour wait is over.

You need to have an actual trigger (e.g. 6pm everyday) for your task, otherwise "wait for idle for" does not make sense.

Now you read it as:

At 6pm everyday, if the computer is not idle yet, wait for another 1 hour to become idle.

• If it becomes idle within that time, let it be idle for 10 minutes and then the task gets started.
• If not, the task will not be triggered.

And just to complicate this a little more, Windows only evaluates if the computer is idle every 15 minutes. So even if you schedule a task at 09:00, with an idle for 1 minute and you make sure you're not doing anything for that whole minute, it may still not activate at 09:01 and may actually not activate until 09:15 depending on when Windows evaluates the idle state.