I've recently built a new computer running Windows 10 with x99 motherboard and for some reasons my Windows went to sleep mode last night for no good reason. When I woke from my sleep the computer greeted me with lock screen demanding a password.

Here's what I saw upon checking event viewer logs:

Event 42, Kernel-Power

The system is entering sleep.

Sleep Reason: Application API

I have the standby mode off in the power settings so I'm not not sure what could be the reason it just goes to sleep like that

It's like I pressed Win+L but I didn't

  • Does this problem happen if you boot into a minimal boot configuration? – Ramhound Apr 1 '16 at 17:46
  • I would have to check this tonight. The PC went to sleep after IDLEing for about 90 minutes last night. And immediately woke up like 2 seconds after according to logs. Weird – keklord Apr 1 '16 at 17:49
  • 1
    Win+L just locks the screen, it does not cause sleep. – Moab Apr 1 '16 at 20:57
  • It says Reason: Application API: So an application triggered this sleep. But which application it is, is something only you can answer. You may be able to find an application event in the eventlog near the time of this event to find out what application triggered this. Also, don't forget scheduled tasks or any "power" application, designed to optimize your system. 90 minutes is 1,5 hours, which sounds like an optimization thingy. Like: If the system is unattended for 1,5 hours, put it to sleep. – LPChip Apr 1 '16 at 20:59

Event 42 is in the System event log. Check for events about the same time in the Application event log. In my case, it looks like the APC PowerChute process is putting the system to sleep (for as yet unknown reasons). The user who posted here describes the symptoms exactly:


  • 1
    Can confirm on this. For me, it was the HP Support Solutions Framework. - Under Event Viewer > Application, search for the string 'PowerEvent handled successfully by the service.' – NBN-Alex Jul 26 '18 at 19:47

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