I decided to finally install Windows 8 on one of my desktop computers. It's Windows 8.1 Pro from the get-go, and I got the Update 1 through Windows Update. It works fine. But my main concern right now is that it wakes up my computer after I put it to sleep. I put it to sleep by pressing the sleep button on my keyboard.
There is a Microsoft KB article about this.
Windows 8 desktop wakes up unexpectedly from sleep or hibernation
Symptoms
A Windows 8 Desktop computer is automatically waking from sleep or hibernation at a certain time even if there is no "ACPI Wake Alarm" system device found by the operating system.
Cause
For Windows 8 desktops or All-in-one computers, under Action Center / Automatic Maintenance, the checkbox is automatically enabled for “Allow scheduled maintenance to wake up my computer at the scheduled time”. Also, the power policy / Advanced settings / Sleep / Allow wake timers will default to Enabled for AC power.
If the desktop machine does not have an “ACPI Wake Alarm” device (or if it is disabled in the BIOS), Windows 8 still uses the Real Time Clock (RTC) to program wake events, assuming the power policy / Advanced settings / Sleep / Allow wake timers is Enabled for AC power.
What's ACPI Wake Alarm device?... I could not locate the "Automatic Maintenance" option.
The option "Allow wake timers" is enabled in Power Options dialog.
But the powercfg /waketimers command says there are no wake timers.
Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.
C:\Windows\system32>powercfg /waketimers
There are no active wake timers in the system.
C:\Windows\system32>
So these options should not matter then, right?
I think it's my network card that wakes up my computer. But why would it do that? I do have WOL (Wake-On-LAN) enabled and I use that occasionally. I had Windows 7 Ultimate before installing Windows 8, and I think I had to enable this feature in BIOS and then in Device Manager. But I think this is set as enabled by default now in Windows 8. So I didn't touch any of those settings. Here's what I found in the System log.
The system has returned from a low power state.
Sleep Time: 2014-09-13T21:08:30.188798700Z
Wake Time: 2014-09-13T21:17:41.262988300Z
Wake Source: Device -Realtek PCIe GBE Family Controller
I believe this is from the last time it woke up unexpectedly. I normally use my mouse to wake up the computer. As I searched through the log, I found that there is an unknown wake source. Here are the last few wake up events.
#
The system has returned from a low power state.
Sleep Time: 2014-09-13T23:27:22.259006200Z
Wake Time: 2014-09-14T09:07:34.293661300Z
Wake Source: Device -USB Root Hub
#
The system has returned from a low power state.
Sleep Time: 2014-09-13T21:08:30.188798700Z
Wake Time: 2014-09-13T21:17:41.262988300Z
Wake Source: Device -Realtek PCIe GBE Family Controller
#
The system has returned from a low power state.
Sleep Time: 2014-09-13T09:56:49.947590500Z
Wake Time: 2014-09-13T10:50:19.258919900Z
Wake Source: Device -USB Root Hub
#
The system has returned from a low power state.
Sleep Time: 2014-09-12T23:16:11.122616600Z
Wake Time: 2014-09-13T07:27:49.265183700Z
Wake Source: Device -USB Root Hub
#
The system has returned from a low power state.
Sleep Time: 2014-09-12T09:09:38.868040700Z
Wake Time: 2014-09-12T14:56:44.339231700Z
Wake Source: Device -USB Root Hub
#
The system has returned from a low power state.
Sleep Time: 2014-09-11T23:22:44.847600700Z
Wake Time: 2014-09-12T08:26:27.666880800Z
Wake Source: Unknown
#
The system has returned from a low power state.
Sleep Time: 2014-09-11T15:04:01.090698200Z
Wake Time: 2014-09-11T16:02:54.300287300Z
Wake Source: Unknown
#
The system has returned from a low power state.
Sleep Time: 2014-09-10T23:35:46.989285000Z
Wake Time: 2014-09-11T09:14:49.250228900Z
Wake Source: Device -USB Root Hub
#
The system has returned from a low power state.
Sleep Time: 2014-09-10T23:09:06.024062600Z
Wake Time: 2014-09-10T23:30:08.602710700Z
Wake Source: Device -USB Root Hub
#
The system has returned from a low power state.
Sleep Time: 2014-09-10T09:56:17.923592700Z
Wake Time: 2014-09-10T17:26:14.339458100Z
Wake Source: Unknown
#
The system has returned from a low power state.
Sleep Time: 2014-09-09T23:22:05.363064000Z
Wake Time: 2014-09-10T09:26:32.681954100Z
Wake Source: Unknown
#
The system has returned from a low power state.
Sleep Time: 2014-09-09T23:12:43.624651300Z
Wake Time: 2014-09-09T23:18:16.367444900Z
Wake Source: Device -Realtek PCIe GBE Family Controller
How can I get more information about this unknown device? How can the system not know what woke it up? And if it is my network card that wakes it up, why would it do that? I didn't have this problem with Windows 7. But now I do with Windows 8 (8.1 Update 1), on the same computer.
Update
In the properties dialog box for the network card in Device Manager, Wake on Magic Packet is enabled, as is Wake on pattern match under the Advanced tab.
But there is the option Only allow a magic packet to wake the computer under the Power Management tab, and it's disabled. I will try enabling this. But isn't this for computers that have more than one network interface?
It just woke up a few hours ago.
The system has returned from a low power state.
Sleep Time: 2014-09-14T12:08:53.237475400Z
Wake Time: 2014-09-14T12:17:48.289129900Z
Wake Source: Device -Realtek PCIe GBE Family Controller
So it is indeed my network card that's waking it. But why? What triggers it? I didn't send any WoL packets to it. Not that I'm aware of anyway. I usually use my router to send WoL commands, and I have not port forwarded WoL, so it should only work locally. It shouldn't be able to wake up over the Internet.
