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HTG Explains: How Windows Uses The Task Scheduler for System Tasks

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While you can use the Windows Task Scheduler to schedule your own automatic tasks, Windows also uses it behind the scenes to perform many system tasks – defragmenting your hard disks when you’re not using your computer, for example.

You can even modify these system tasks to tweak Windows to your liking – for example, you can change how often Windows creates system restore points. Third-party programs also often use the Task Scheduler for their own tasks.

What’s the Task Scheduler?

The Task Scheduler is a Windows component that can automatically run tasks at a specific time or in response to a specific event. For example, tasks can be run when the computer starts or when a user logs in.

Many Windows system tasks need to run regularly – for example, Windows automatically defragments your hard disks at regular intervals. Instead of writing a defragmentation scheduler program that always runs in the background and waits to defragment your hard disks Windows sets up a scheduled task that automatically runs the defragmenter in the background at a specific time. The Task Scheduler launches many other Windows system tasks in the same way.

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Instead of implementing this functionality in each program that needs to run automatically, Windows tells the Task Scheduler to run them. Third-party applications can also add their own scheduled tasks here – you can even add your own.

Exploring System Tasks

Windows system tasks aren’t a black box – you can open the Task Scheduler and examine them yourself. To open the task scheduler, type Task Scheduler into the Start menu and press Enter.

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Browse to the Task Scheduler Library\Microsoft\Windows folder – you’ll see subfolders for a variety of Windows system tasks.

For example, the Defrag folder contains the task that automatically defragments your hard disks on a schedule. When you change the scheduled time in the Disk Defragmenter application, Windows updates this scheduled task with your new settings. If you disable the Run on a Schedule option in the Disk Defragmenter, Windows will disable this system task.

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Scheduled tasks don’t just run at specific times, though – Windows and the Task Scheduler are smarter than that. For example, the scheduled disk defragmentation task doesn’t start defragmenting your hard disks if you’re using the computer – it waits and runs the defragmentation operation only if your computer is idle (in other words, if no one is using the computer.) If you come back to your computer while it’s being defragmented, the defragmentation will be paused until you leave the computer again.

You can view details like this by double-clicking a scheduled task. You’ll find the idle-related restrictions on the Conditions tab.

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Tasks can also run in response to events. For example, the SystemSoundsService task in the Multimedia folder runs when any user logs on – it provides the login sound and other Windows system sounds.

Other scheduled tasks run in response to other events, such as specific event IDs in the Windows event log. Windows watches for the event ID generated by another program and runs the task when the specific event ID appears.

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Tasks for Third-Party Applications

Third-party programs often use the Task Scheduler for their own tasks, too. For example, Google Update (used to update Google Chrome, Google Drive, and other Google applications) installs a service that automatically runs Google Update. Adobe Flash uses a similar service to automatically check for updates in the background.

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Some programs don’t use scheduled tasks, although they should. For example, Java uses a program named jusched.exe that always runs in the background instead of a scheduled task. This is one of the many problems with Java.

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 09/3/12

Comments (16)

  1. michel

    My Task Scheduler is broken. I get an error message and cannot access any scheduled tasks. Is there some way to reset it back to factory?

  2. kwe

    I really like your HTG Explains articles. Thorough and accurate.

  3. Nadia

    An excellent explanation.Thank you.

  4. r

    @michel

    difficult to say unless one knows the error message or error code.
    -perhaps TaskSchedulerRes.dll is corrupt.

  5. Sanjay

    HTG really helped me to resolve the printer(footer) issue.Thank you

  6. Shubham

    Just love HTG articles …. thumbs up guysss for ur articles . they really provides a gr8 understanding..

  7. wagonman

    Much appreciated. Nice to know what Windows is up to and doing in the dark.

  8. Mac

    Nice tutorial! Thanks!

  9. Jean

    When I click on Start menu, there is nowhere that I can type into : all I can do is select from a list.
    So I can’t find the task scheduler.

  10. Randy

    On the right side of your Start Menu you should have an entry called “Administrative Tools”. If you click on that you will find Task Scheduler.If you dont have the entries on the right side you should right click the start button, choose properties and once you have that open choose start menu and then customize. Scroll down the list of entries till you see System Administrative tools and choose to display on the all programs menu and the start menu and close it out and you will have your Administrative Tools/Task Scheduler on the right side of the start menu. This is for Jean and I use Windows 7 so those are the instructions for that OS. Good Luck.

  11. George

    A really thorough explanation………..how do I find task scheduler in Windows XP?

  12. edward

    hey i went my password

  13. edward

    hey i need my password now i m not being mean to you ok

  14. spike

    @edward: you ‘went’ your password.. where did you ‘went’ with it LOL. If I had it I would post it :-)

    Nice article, BTW.

  15. avz10

    Could someone please help.
    Is it possible to use Task Scheduler for e.g. CCleaner and set it that it opens and starts by itself?

  16. maria antony

    Hi,
    Can any one help me?when I open my email a dialog box show[''security warring''You have requested an encrypted page that contains some unencrypted information that you see or enter on this page could easily be ready by third party] can any one tell how it happen in to my computer?and when I open my email some third party watch me what I’m doing, how could be possible?any way to block this?

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