My Windows 10 build 10240 keeps randomly waking up itself from hibernation. This happens sometimes right in a minute after the computer successfully enters hibernation (but never immediately after it), sometimes only hours later, in the middle of the night. Sometimes everything works fine and Windows 10 doesn't wake up until the power switch is pressed again next morning.
When the computer resumes from hibernation unexpectedly and I put it into hibernation again, it usually wakes up again in a minute or so. It does that until I prevent Windows 10 from booting by either power-cycling, or by forcing the computer to boot into the BIOS instead of Windows 10. This tells me that it's Windows 10 that somehow "schedules" a wake up from hibernation or something - and when it's not allowed to boot, it can't reschedule another wake-up, so the cycle gets broken and the issue temporarily goes away.
Unfortunately I can't figure out the exact reason of the unexpected resume, because when it happens "powercfg -lastwake" does not list any wake events. The Event Log does not help me in diagnosing the cause of the wake-up either, because the Power-Troubleshooter entries list the "Wake source" every single time as "Unknown". Other than that the entries only say that "The system has returned from a low power state" and list the sleep and wake times.
The behavior is unexplainable to me, because I've the "Allow this device to wake the computer" option disabled on all devices. This is also confirmed by "powercfg.exe /devicequery wake_armed" which prints "NONE". I've also disabled "Wake timers" and "Hybrid sleep", and set the "When sharing media" option to "Allow the computer to sleep" in the current power plan options. So theoretically there should be no sources or events in the system whatsoever that would be allowed to wake the computer from hibernation. Still, something does it from time to time.
Network activity can't be the cause of the issue either, because I'm experiencing the unexpected wakeups also when I disconnect the network cable from the computer after it gets to sleep. Actually, once I've disconnected all USB devices (including mouse and keyboard) from the computer, and it still woke up in a minute or so from hibernation. That again confirms that it must be some internal device or mechanism that triggers the wakeup.
I've also checked the Task Scheduler and couldn't find a task that would be allowed to wake the computer from sleep. However, my understanding is that with the wake timers disabled this shouldn't matter anyway.
sfc /scannow doesn't find any issues with the system either. I've all the latest drivers installed for my devices. There are no unknown or unworkable devices listed in the device manager.
I've also experimented with setting the power management option in the UEFI BIOS to OS controlled and BIOS controlled, with no obvious change. Of course in the BIOS controlled mode I've set all "Resume by" entries (RTC Timer, USB, PCI, PS/2, etc) to Disabled, meaning no hardware event was allowed to wake the computer. Still it randomly resumed from hibernation.
I've experienced the random resumes with practically all Windows 10 Insider builds from end of May (when I installed the first preview over a Windows 8 Pro), but am only reporting it now, because it seems even the RTM version won't fix it.
Do you have any idea why Windows 10 wakes itself for no apparent reason from the hibernation randomly, and how I can make sure that once I hibernate the system it does not come back on for any reason whatsoever until I manually tell it to do so by pressing the power button on the computer?