I've tried everything here.
All my keyboard/mouse devices have "Allow this device to wake the computer" unchecked.
Wake timers are disabled.
Automatic Maintenance is disabled.
Despite all this, my PC still consistently wakes up in the middle of the night around 2-5 AM.
The powercfg command returns a wake source count of 0.
The event log lists the wake source as "unknown".
Is my computer haunted? This same thing has been happening with this same system all the way back to Windows 7 (across multiple clean installs), and it's also happening with my laptop that runs Windows 10. I'm really getting irritated by being woken up in the middle of the night by loud fan noises. Any ideas what might be going on?
If you are sure you have checked everything and even disabled Wake on LAN on your network card, then there is only one other thing I can think about. The BIOS is set to wake your PC at a certain time.
Depending on your BIOS/UEFI, there could be an option in your powermanagement which state that your PC has to be started at a certain hour every day. I did this in the past, to make sure it would wake up from any state, even shutdown, in the morning.
For the rest, the only other thing you could do, is stay awake yourself and when the PC wakes up, use powercfg /request to maybe catch which program woke your PC.
A while back, I had Teamviewer waking up my PC every 30 minutes, but they have fixed this by now. Of course, you could be using something else that is also waking up your PC, because it needs to check something. (Any kind of Software Update that is being run, or a program that wants to do a maintenance on your system, or anything else...)
A place to check this, is at: Computer Management -> System Tools -> Task Scheduler
Check here for any scheduled task that could wake up your pc.
Much luck! I hope you find it.
PS: An other thing you could do, is replacing your fans with noiseless ones. I sleep in the same room as my PC, and it is about 2 meters away from my head. It can wake up in the middle of the night without waking me up. And else, you will have no other choice than to put your PC without power during the night. Just shut it down and use an outlet with a switch. This way, you will have a goods nights rest.
It's 11AM here now, and according to the event log, my PC woke up three times before the time I woke it up manually - 2AM, 4AM, and 7:30AM. Wake source "unknown" every time.
Scheduled tasks shouldn't be waking it up because I have wake timers turned off.
I don't think I've ever set that in the BIOS, and it happens several times each night.
Most of my fans are noiseless at normal levels, but for some reason my fan controller spins them all up to 100% at startup for a few seconds, which is when my two H100i exhaust fans sound like jet engines...
If it is always at especially those exact times, I still think it's a schedule that is waking your system, even when wake timers are turned off.
Or something else in your network is waking up your PC, although, when you have disabled Wake on LAN on your NIC, it shouldn't be possible for an external device to do this.
Nevertheless, it can still be a third party program, even with wake timers turned off, that's waking up your PC. Like in my case with Teamviewer. There wasn't anything mentioned in the Schedule, but because I kept it active so I can take control of my PC when it was awake, it send out some signal every 30 minutes that woke my PC. I'm glad they quickly fixed this problem for me, and others.
Maybe you have some program(s) running in the background that is waking your PC, without putting anything in the Schedule of Windows.
Or, it could be something else completely. When Windows 8.1 came out, a lot of us had trouble to keep our PCs sleeping. Back then, it was a combination of problems we had. I could get my PC to sleep, when I disabled SkyDrive. Afterwards, I discovered that another program that did a very good job maintaining my Windows 8, deleted something in my registry with Windows 8.1 which broke SkyDrive.
Those problems are almost impossible to track, unless you do a clean install, and then only install one program at a time, until you find the cause of your problem. In your case, it means installing one program a day, to make sure you don't miss the program that is causing the problem.
And... If you don't want to do this, the best way to keep your PC off, is doing a shutdown before you go to bed. Depending on your system, it should stay off until you press you powerbutton when you need it again the next day.
And yes, my system's fans do the same thing when the PC comes alive. My fans turn full blast for a second or two before slowing down. Luckily, my fans don't make too much noise, but when I'm awake, I can clearly hear the difference.
