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At my workplace, I fully shut down my Windows 8 machine each night before going home. The last couple of mornings, it was turned on when I arrived. Is there some kind of Deep Magic that Windows 8 can use to turn itself on, or is this a clear sign that someone has been turning on my computer before I get to it?

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I'm not convinced that it is caused by Windows 8 but by something called Wake-On-LAN –  Darius Jul 3 '13 at 15:55
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Sounds like your computer is configured to turn on in order to recieve updates pushed my your workplace administrator. Just ask whom ever handles technical support at your work. Windows 8 isn't turning on your computer. –  Ramhound Jul 3 '13 at 15:56
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I was struggling with a Win8 machine turning itself on for quite a while. powercfg /lastwake is a good place to start. In my case, it were stupid scheduled tasks that were allowed to wake the machine. –  Oliver Salzburg Jul 3 '13 at 16:26
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I'm pretty sure this is how SkyNet started –  jsedano Jul 3 '13 at 16:43
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I think this is a side effect that Windows 8 doesn't fully power off by default, and instead uses some sort of hybrid sleep/hibernate. –  Drake Clarris Jul 5 '13 at 14:06
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10 Answers

up vote 32 down vote accepted

There are a handful of ways a machine can turn itself on from on "off" state. Firstly, modern PCs never truly are off. See ACPI for more information. The computer hardware (not the OS) is checking to see if you press the power button. Other devices can send ACPI signals, such as keyboards with power/sleep buttons. Computer BIOSs can turn a computer on after recovering from a power loss, which is good for machines that need to be on all the time. Wake on LAN (WoL) is another method which can cause a machine to power on.

As for what is causing your machine to wake up, its hard to say. Check your Windows system event logs and see if there are any entries after the time you leave till the time you get in that look pertinent. Your BIOS, might also have some information in its logs.

And the next question, might sound silly, but are you sure you are doing a shutdown and not a sleep?

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Like @HS said, looking things up in the Event Viewer is useful. –  Kevin Jul 3 '13 at 16:23
    
Also, looking through my logs, it looks like my computer really was turning on while I was away. But I was wondering if I had accidentally hit "Sleep" instead of "Shut Down" as well. =P –  Kevin Jul 3 '13 at 19:43
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Although to give a more accurate description, the hardware really isn't "checking" to see if you press the power button. That gives the impression that it's actively polling, whereas the power button is really just shorting the two pins on your motherboard that start it up. –  hexparrot Jul 3 '13 at 22:20
    
Yes, shorting the pins. But the microprocessor is definitely checking whether the pins are shorted (or rather, whether the relevant pin is pulled down to ground). –  Mels Jul 4 '13 at 13:42
    
As a clarification pertinent to this question (and mentioned in a comment on the question): it IS possible for Windows 8 (and other operating systems) to wake the computer, even from the "shut down" state. Often times, this occurs via scheduled tasks. Whether that's what's happening here, or it's one of the many possible other methods Keltari mentioned, I can't say. –  Nick Jul 6 '13 at 20:26
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The only methods a standard PC can "turn itself on" include:

  • Wake-on-LAN enabled in the BIOS and someone on the network broadcast a WOL packet to it.

  • Most PCs have a "wake up timer" in the BIOS whereby they can automatically power on at a specific time of day.

  • Some PCs have a feature where incoming activity on a 56k modem could trigger power on - doubt this applies to your situation.

  • Some PCs have out of band management hardware such as Intel AMT that can allow administrative personnel to do things remotely like power on the system, even if it is off.

So automatic or unattended power on will involve either someone/something remotely accessing your system or BIOS settings.

EDIT: @Oliver Salzburg has taught me something here - I did not know scheduled tasks could wake a system. Do check that.

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is that modem flex or x2? sigh... im old –  Keltari Jul 3 '13 at 16:10
    
Really. Some times ago (Windows 7 era) my home desktop has a 56k modem card connected to receive fax, and the PC really start itself frequently. Needed to disable PCI wake up... –  Alvin Wong Jul 4 '13 at 1:51
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No, Windows cannot, but BIOS level functions can. Some more sophisticated BIOSes support wake timers (computer wakes up every morning at 6AM), and some peripherals can wake the system as Darius mentioned. Otherwise when Windows is not booted, no, there is nothing it can do to effect its power state.

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Windows can set those BIOS timers you mention. It is used for scheduled tasks. –  Zan Lynx Jul 3 '13 at 17:34
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true, but it can only manipulate them when actually booted. if the OS is asleep or hibernated, it can control the bios functions via ACPI, but when its fully powered down, only the BIOS itself can assert any control. –  Frank Thomas Jul 3 '13 at 18:08
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If the operating system wanted to, it could set a timer for every 15 minutes, wake up just a little bit to check on things like reading email for example and then sleep again. Just like a cell phone does. –  Zan Lynx Jul 3 '13 at 22:39
    
agreed. windows systems which are asleep, or hibernated do that all the time, to run scheduled tasks or update checks. But windows cannot boot itself. –  Frank Thomas Jul 4 '13 at 2:57
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I noticed the same behavior on Dell OptiPlex 740 machines that I worked with. Since I had started out with Windows 7, I also had no way to distinguish if it was an OS thing. Someone figured it out how to turn it off here:

http://forums.cnet.com/7723-13974_102-585460/optiplex-740-turns-on-by-itself/

Please access BIOS by pressing F2 key at Dell logo. Navigate to 'Auto Power Time' option listed under 'Power Management' and press Enter. Check if the time is displayed as 5.30 AM.

Navigate to 'Auto Power On' and check if 'Everyday' or 'Weekdays' is selected. Use the left arrow key to highlight 'Off' and press Enter. Press 'Esc' key, select 'Save/Exit' and press Enter.

So that is one answer - that manufacturers have set the BIOS autostart on weekdays as the default. Exactly how widespread this practice is, and when they started doing that, is a curious question.

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  1. Go to My computer>Manage>Event Viewer. Here you have history of computer, like when was computer started, which application was started etc etc

  2. If you have authority, check your company security camera, to see if someone is messing up with your computer :-)

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I found this tutorial that discusses using the Even Viewer in Widnows 8: computerperformance.co.uk/win8/windows8-event-viewer.htm –  Kevin Jul 3 '13 at 16:23
    
Yes you can just scroll to the date and see when the computer was started. By switching tabs "system" "Applications" , you can also see which application was started when. –  H S Jul 3 '13 at 16:37
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Keep in mind Management Appliances like the K1000 that may be in place at your work might have a power policy schedule implemented.
http://www.kace.com/products/systems-management-appliance/features/power-management

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In my case, my laptop was resuming from sleep because of a scheduled task.

To resolve it, I followed the steps described in this Microsoft Community Forum post:

  1. Open Task Scheduler by searching for it from Start.
  2. In the left panel, navigate to:
    • Task Scheduler (Local)
    • Task Scheduler Library
    • Microsoft
    • Windows
    • TaskScheduler
  3. In the top center panel, double-click on "Regular Maintenance"
  4. In the new window entitled "Regular Maintenance Properties (Local Computer)" , select the "Conditions" tab
  5. Unselect "Wake the computer to run this task"
  6. Press OK
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I am using Windows 8.1. If Windows 8 users can use Alarm app, this tip may also work on their computer. My computer was suddenly turned on by itself when I set my Alarm app to ring at 5 in the morning. I had shut down the computer the night before. Since that time, I have been using this app to automatically turn on my computer at specific time.

Edit: I have just checked Alarms app's faq page. The reason why a PC is turned on automatically is not only because of alarms app, but also because the PC supports InstantGo. I have checked my PC and I guess this is also the reason why my computer is turned on automatically.

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Check for your BIOS settings. You will find a solution to restart after SHUT DOWN. If your are HIBERATING or SLEEP then go to power settings in Windows.

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  • computer is machine
  • without power supply or internal powersuppy it can TURN ON
  • there are some machines who use powerfull batteries to turn on machine on perticular time but this are internal
  • some programs or routines do this task
  • some one gets started your machine befor you reach

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    +1 for "computer is machine". +2 for it being able to TURN ON without power supply. +3 for general feeling of wtf. :-) –  localhost Jul 5 '13 at 6:48
        
    I hate it when some one gets started my machine befor I reach –  oscilatingcretin Dec 26 '13 at 17:55
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