I created a new Task in my task scheduler and I wanted it to be running only if the computer is idle for 10 min.

but then I saw this checkbox which I don't understand what it does :

enter image description here

The help says :

If a task is set to start only if the computer is idle for 30 minutes, and the task waits for the computer to be idle for 10 minutes, then the task will launch in 5 minutes only if the computer has been idle for 25 minutes prior to the time the trigger was activated. The task will not start if the computer enters an idle state 5 minutes after the trigger is activated.

Sorry I don't understand this explanation. ( where the 5 min came from ???)

can someone please shed light ? ( in simple words)

  • It seems most confusion here arises from a rather strange use of the word "trigger". To most English users, "the task has been triggered" and "the task has executed" are synonymous. The event (which may be a compound event) which causes a task to execute is its trigger, not just one of the sub-events.
    – kreemoweet
    Aug 23, 2022 at 20:31

6 Answers 6


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.

  • Why do you mention re-run tasks in your answer ? the setting for this is in another tab.
    – Royi Namir
    Jul 6, 2014 at 7:44
  • at first - there is no task triggered
    – Royi Namir
    Jul 6, 2014 at 7:45
  • I don't mention 're-run tasks' in my answer.
    – mmmason
    Jul 6, 2014 at 7:45
  • ...if the computer has been idle for 10 minutes or more when the task is triggered,...
    – Royi Namir
    Jul 6, 2014 at 7:47
  • 4
    I don't understand. All Scheduled Tasks get triggered at the time that they are specified to run. If you set a Scheduled Task to run at, say, 11:15 then it will be triggered at 11:15. If there are conditions set (such as the computer having to be idle), then although the task is triggered it might not necessarily execute.
    – mmmason
    Jul 6, 2014 at 7:50

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.


I can explain this much more clearly...

Imagine you're sitting beside a busy roadside. You're bored, so you play a game: You tell yourself that if no cars drive past for one whole minute - you win!

The thing is, you're probably not going to win if you're only sitting there for a few minutes. But if you waited there for many hours, you'd have much more chance of winning.

So there are two parameters involved here:

  1. How long does the break in traffic need to last?
  2. How long you are you going sit there waiting for a break?

It's exactly the same with Task Scheduler:

  1. How long does the break in activity need to be?
  2. How long should the computer spend waiting for such a break?

A graphical explanation to go along @mmmason's answer:

Idle Condition

Source: Microsoft


I'm also trying to understand and have parsed all the comments the best I could. Paraphrasing the "help" to some extent: First, definitions are important. Some have alluded to this. The "trigger" can be anything and is probably easier to understand the descriptions if it's something other than "Idle" when adding the Idle Conditions. Also, I found the negative case descriptions harder to follow. So here is the result:

IF a task is triggered (by any trigger condition and not just Idle) [at time=0]
IF a Condition is set that the computer be Idle for some period X.
    {IF the Idle time Condition is TRUE at time=0 - Execute the task
    the Idle Condition is FALSE at time=0 - Do not execute the task
    {IF "Wait for idle for" is set to Y
     THEN watch for the idle time to reach X during Y
    {ELSE the computer does not reach the specified idle time while watching

Start the task if the computer idle time upon trigger is >= 30 minutes. Otherwise the task watches the computer idle time for 10 more minutes. If the computer idle time reaches 30 minutes within that 10 minute watch, the task is started. Otherwise the task is not started.

Here's a set of examples: enter image description here

At least that's how I've been able to interpret it.

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